Automatic adjusting method for cooling forming of filaments

Abstract

The invention belongs to the field of chemical fiber spinning, and relates to an automatic adjustment method for strand cooling forming, which comprises the step of variety change by stopping spinning, and when the variety change by stopping spinning is carried out, the following steps are executed: calculating the theoretical oil frame height of the changed variety, and measuring the actual oil frame height; comparing the actual oil rack height with (the theoretical oil rack height + / -the height deviation value); if the actual height of the oil rack is lt; (theoretical oil rack height-height deviation value), increasing the height of the oil rack; if the actual oil rack height is gt; (the theoretical oil frame height + the height deviation value), reducing the oil frame height; if (theoretical oil rack height-height deviation value) < = actual oil rack height < = (theoretical oil rack height + height deviation value), the oil rack height is kept unchanged; theoretical oil rack height = empirical constant * curing distance; and the value range of the empirical constant is 1.5-2.5. When the spinning variety is changed, the height of the oil frame can be automatically adjusted, and the excellent filament cooling forming effect can be guaranteed.

Description

Technical Field

[0001] The invention belongs to the field of chemical fiber spinning and relates to a method for automatically adjusting the cooling and forming of a filament. Background Art

[0002] During the melt spinning process, after the melt is extruded from the spinneret, it is subjected to the combined effects of winding forces (winding tension, gravity, air resistance, inertia, and surface tension) and cooling air, causing it to thin and lengthen, solidify, and form a filament. This filament is then bundled and oiled, and then subjected to subsequent stretching and shaping processes. Currently, this bundling and oiling process uses an oil nozzle. The oil nozzle is the point where the filaments are bundled. Because the oil nozzle is fixed to an oil rack, the rack must be located below the solidification point of the filaments. The position of the oil rack has a significant impact on the temperature at the top of the rack and the cooling and forming of the filaments. Furthermore, when changing the spinning variety, due to the different thicknesses and linear densities of the individual filaments (e.g., 83dtex / 72f vs. 111dtex / 36f), the specific surface area of ​​the individual filaments also varies, resulting in different rates of heat exchange with the outside world and different cooling speeds. Therefore, the required oil rack position and cooling air speed also vary to achieve optimal filament cooling and forming. Therefore, it is important to study how to adjust the oil rack position and cooling air speed to achieve optimal filament cooling and forming.

[0003] The utility model patent with patent announcement number CN222043429U discloses an automatically height-adjustable spinning oil rack for high-elastic nylon 6, comprising two fixed frames and an upper oil nozzle bracket, a lower oil nozzle bracket and a wire guide hook bracket arranged between the two fixed frames. Each of the fixed frames comprises a vertical frame, two slide rails and three cross bars. The two slide rails are arranged in parallel on the vertical frame. The slide rails are provided with scale marks. The two ends of the three cross bars are respectively slid between the two slide rails through a slider. The sliders are each provided with a scale identification sensor. A scissor-type lifting device is provided between the upper and lower adjacent cross bars. The upper oil nozzle bracket, the lower oil nozzle bracket and the wire guide hook bracket are sequentially arranged between the two fixed frames from top to bottom, and the two ends are respectively fixed on the cross bars. The scale identification sensor and the scissor-type lifting device are both connected to a controller. The working method of this utility model is as follows: the staff inputs the height between the upper nozzle bracket, the lower nozzle bracket and the wire guide hook bracket into the controller according to the type of silk thread, identifies the height of the cross bar through the scale recognition sensor, and then transmits the data to the controller. The controller judges the height of the cross bar according to the data and controls the extension and retraction of the cylinder. When the cylinder is extended, the hinged fork arm extends, and the cross bar rises and is fixed by the fork arm. When the cylinder contracts, the cross bar descends, thereby controlling the lifting and lowering of the upper nozzle bracket, the lower nozzle bracket and the wire guide hook bracket, thereby 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 a change in variety, it is necessary to know the working oil rack height of the changed variety in advance, and then manually input this known working oil rack height, and then use the scale recognition sensor to identify the height of the cross bar, and adjust the oil rack height to the working oil rack height. If the working oil rack height of the changed variety is unknown, it will affect the cooling and forming effect of the wire strip, and the speed of the cooling air cannot be identified and adjusted. Even if the oil rack height is adjusted to the maximum range, it cannot compensate for the change in the cooling air speed, which will also affect the cooling and forming effect of the wire strip.

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

[0006] The purpose of the present invention is to solve the above problems existing in the prior art and to provide a method for automatically adjusting the cooling and forming of a wire strip.

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

[0008] A method for automatically adjusting yarn cooling and forming includes the steps of stopping spinning to change the yarn type (the yarn type change can be a change in yarn thickness and / or single yarn linear density of the same type of polymer, or a change in spinning of different types of polymers, such as a change from polyester spinning to polyamide spinning). When stopping spinning to change the yarn type, the following steps are also performed:

[0009] Calculate the theoretical oil rack height of the changed product and measure the actual oil rack height (theoretical oil rack height and actual oil rack height both refer to the distance from the top of the oil rack to the roof);

[0010] Calculate the theoretical oil rack height of the changed product and measure the actual oil rack height;

[0011] Compare the actual oil rack height with (theoretical oil rack height ± height deviation value);

[0012] If the actual fuel rack height is less than (theoretical fuel rack height - height deviation value), increase the fuel rack height until (theoretical fuel rack height - height deviation value) ≤ actual fuel rack height ≤ (theoretical fuel rack height + height deviation value);

[0013] If the actual fuel rack height is greater than (theoretical fuel rack height + height deviation value), reduce the fuel rack height until (theoretical fuel rack height - height deviation value) ≤ actual fuel rack height ≤ (theoretical fuel rack height + height deviation value);

[0014] If (theoretical oil rack height - height deviation value) ≤ actual oil rack height ≤ (theoretical oil rack height + height deviation value), the oil rack height remains unchanged;

[0015] The calculation formula of the theoretical oil frame height is as follows:

[0016] Theoretical oil frame height = empirical constant x curing distance; the value range of the empirical constant is 1.5-2.5;

[0017] Curing distance × × ×1000, the unit of the curing distance is mm; the curing distance refers to the distance from the curing point of the filament to the spinneret plate;

[0018] Wherein, d0 is the spinneret hole diameter, the unit is m; t1 is the temperature of the melt out of the spinneret hole, the unit is ℃; t2 is the glass transition temperature of the filament (usually when the glass transition temperature is lower, the filament is cured), the unit is ℃; t is the temperature of the cooling air, the unit is ℃; G is the discharge amount of a single spinneret hole, the unit is kg / h; C is the specific heat capacity of the melt (when the same kind of polymer is spun, a fixed value is taken, for example, when PET polyester is spun, C takes a fixed value of 2.2), the unit is kJ / (kg·℃); h is the heat transfer coefficient, which takes a fixed value of 135 kJ / (m 2 ·h·℃); e is the base of natural logarithm, which takes a fixed value of 2.718; d0, t1, t2, t, G are obtained and input into the SMU setter manually or automatically according to the actual equipment and process.

[0019] The principle of the application is that the single filament is still in a high-temperature state when it is just extruded from the spinneret plate, the farther away from the spinneret plate, the lower the temperature of the single filament, under the action of a certain cooling air, the distance between the oil frame and the spinneret plate is fully utilized for cooling, which can save the cooling air resources and reduce the cooling cost; when the oil nozzle is used for oiling and bundling below the position of the filament curing point, since the oil nozzle is installed on the oil frame, the temperature at the top of the oil frame should be within a suitable range to ensure the cooling and forming effect of the filament, for example, the CV value of the unevenness of the filament reaches the requirement, the application quantitatively calculates the theoretical oil frame height of the changed variety by pre-inputting the corresponding parameters, and the temperature at the top of the oil frame is maintained within a suitable range through automatic adjustment of the oil frame height, thereby realizing excellent cooling and forming effect of the filament.

[0020] As a preferred technical solution:

[0021] The method for automatically adjusting the cooling and forming of the filament as described above, with the value of the empirical constant changing within the range of 1.5-2.5, the unevenness CV value of the filament after cooling is tested, when the unevenness CV value of the filament reaches the minimum, the corresponding empirical constant value is the optimal empirical constant value, and the corresponding preset temperature is the optimal preset temperature.

[0022] In the method for automatic adjustment of yarn cooling and forming as described above, the theoretical oil rack height of the changed variety is calculated by an SMU setter (SMU stands for Setting Monitoring Unit, and the SMU setter is a monitoring and setting system frequently used in filament production equipment such as polyester), the actual oil rack height is measured by a rangefinder, and the actual oil rack height is compared with (theoretical oil rack height ± height deviation value) by the SMU setter.

[0023] In the above-mentioned method for automatically adjusting the cooling and forming of a wire strip, the height deviation value is 50-100 mm.

[0024] The method for automatically adjusting the cooling and forming of a filament as described above is characterized by further comprising a spinning process performed after the variety is changed;

[0025] During the spinning process, the temperature of the top of the oil rack is set to a preset temperature, and the actual temperature of the top of the oil rack is monitored in real time. The actual temperature of the top of the oil rack is compared with (the preset temperature of the top of the oil rack ± the temperature deviation value); the preset temperature is 25-30℃, and the temperature deviation value is 1-2℃;

[0026] If the actual temperature at the top of the oil rack is less than (the preset temperature at the top of the oil rack - the temperature deviation value), the oil rack height is reduced, and at the same time, the cooling air valve opening is reduced. Reducing the cooling air valve opening can reduce the cooling air speed until (the preset temperature at the top of the oil rack - the temperature deviation value) ≤ the actual temperature at the top of the oil rack ≤ (the preset temperature at the top of the oil rack + the temperature deviation value), and the cooling air valve opening is set to a minimum value. When the cooling air valve opening reaches the minimum value, if the actual oil rack height is greater than (theoretical oil rack height + the height deviation value) or the actual oil rack height is less than (theoretical oil rack height - the height deviation value), an alarm is issued to indicate that the cooling air supply system is abnormal, such as abnormal filter cleanliness or filter uniformity of the air supply system, and the machine is shut down to inspect the cooling air supply system.

[0027] If the actual temperature at the top of the oil rack is greater than (the preset temperature at the top of the oil rack + the temperature deviation value), the oil rack height is increased, and at the same time, the cooling air valve opening is increased. Increasing the cooling air valve opening can increase the cooling air speed until (the preset temperature at the top of the oil rack - the temperature deviation value) ≤ the actual temperature at the top of the oil rack ≤ (the preset temperature at the top of the oil rack + the temperature deviation value), and the cooling air valve opening is set to 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 + the height deviation value) or the actual oil rack height is less than (theoretical oil rack height - the height deviation value), an alarm is issued to indicate that the cooling air supply system is abnormal, such as abnormal filter cleanliness or filter uniformity of the air supply system, and the machine is shut down to inspect the cooling air supply system.

[0028] If (the preset temperature at the top of the oil rack - the temperature deviation value) ≤ the actual temperature at the top of the oil rack ≤ (the preset temperature at the top of the oil rack + the temperature deviation value), the oil rack height and the cooling air valve opening remain unchanged, and normal spinning continues.

[0029] During the spinning process after spinning, the height of the oil rack and the opening of the cooling air valve are automatically adjusted, which not only fully utilizes the distance between the oil rack and the spinneret for cooling, reducing the cooling cost, but also enhances the cooling effect through the cooling air, improves the cooling efficiency, and can also keep the temperature on the top of the oil rack within a suitable range to ensure the cooling and forming effect of the filaments.

[0030] As described above, a method for automatically adjusting the cooling and forming of a wire strip is used. As the value of the empirical constant changes within the range of 1.5-2.5 and the value of the preset temperature changes within the range of 25-30°C, the CV value of the wire strip unevenness after cooling is tested. When the CV value of the wire strip unevenness reaches the 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 a method for automatic adjustment of wire strip cooling and forming, 0%<cooling air valve opening ≤100%, the cooling air valve can be fully opened but not fully closed. If the wind speed is still insufficient when the cooling air valve is fully opened, it means that the filter of the air supply system is clogged and needs to be shut down for processing.

[0032] In the method for automatic adjustment of wire strip cooling and forming as described above, the preset temperature setting of the temperature of the top of the oil rack is completed through the SMU setter, and the actual temperature of the top of the oil rack is obtained through the temperature sensor. If there are multiple temperature sensors, the average value of the multiple 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, and the actual temperature of the top of the oil rack is compared with (the preset temperature of the top of the oil rack ± the temperature deviation value) through the SMU setter.

[0033] In the above-mentioned method for automatic adjustment of wire strip cooling and forming, the increase and decrease of the opening of the cooling air valve are completed through the SMU setter and the second execution controller, and the second execution controller is connected to the SMU setter and the cooling air valve at the same time.

[0034] A method for automatic adjustment of wire strip cooling and forming as described in any of the above items, increasing and decreasing the oil rack height are completed by the SMU setter, the first execution controller, the cylinder, the oil rack slide rod and the sliding sleeve, the sliding sleeve is fixed on the side of the oil rack, the oil rack slide rod is fixed vertically, the sliding sleeve is slid on the oil rack slide rod in an up and down manner, the working end of the cylinder piston rod is fixedly connected to the bottom of the oil rack, the first execution controller is connected to the SMU setter and the cylinder at the same time, and the SMU setter controls the working end of the cylinder piston rod and the oil rack to move upward or downward through the first execution controller, thereby completing the reduction or increase of the oil rack height 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 quantitatively calculates the theoretical oil rack height of the changed variety by inputting corresponding parameters, and automatically adjusts the oil rack height and automatically monitors the cooling operation of the yarn within the set range, ensuring that the CV value of the yarn unevenness after cooling and forming reaches an excellent level.

[0037] (2) During the spinning process, the method provided by the present invention monitors the cooling condition of the filaments and automatically adjusts the oil rack height and the opening of the cooling air valve to ensure excellent cooling and forming effects. When the adjustment range is exceeded, an alarm is issued to prompt timely inspection and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 3D schematic diagram of the automatic adjustment device for wire strip cooling and forming according to Example 1;

[0039] Figure 2 Schematic diagram of the principle of the automatic adjustment device for wire strip cooling and forming of Example 1, where the green arrow represents the airflow direction of the cooling air, the blue arrow represents the direction of the wire strip, and the red arrow represents the direction of the compressed air flow;

[0040] Figure 3 Schematic diagram of the partial structure of the automatic adjustment device for wire strip cooling and forming according to Example 1, where the red arrows represent the flow direction of the compressed air;

[0041] In the figure, 1-right side plate, 2-filter screen, 3-top plate, 4-left side plate, 5-oil rack slide, 6-pressure stabilizing chamber, 7-air valve, 8-oil rack, 9-oil nozzle, 10-SMU setter, 11-distance meter, 12-temperature display screen, 13-deviation display screen, 14-temperature sensor, 15-sleeve, 16-cylinder, 17-first execution controller, 18-second execution controller, 19-alarm, 20-thread strip, 21-spinning assembly, 22-wire guide hook, 23-fixing rod, 24-oil nozzle slide, 25-wire guide hook slide, 26-bottom plate. DETAILED DESCRIPTION

[0042] 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.

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

[0044] (1) CV value of yarn unevenness: The test is carried out in accordance with GB / T 14346-2015 "Test method for yarn unevenness of chemical fiber filaments - Capacitance method".

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

[0046] (3) Half inhibition value: Tested in accordance with GB / T 14346-2015 “Test method for unevenness of chemical fiber filament yarn - Capacitance method”.

[0047] (4) Dyeing uniformity: Tested in accordance with GB / T6508-2015 “Test method for dyeing uniformity of polyester filament yarn”.

[0048] Example 1

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

[0050] The side-blowing air box is a rectangular parallelepiped structure formed by sequentially connecting the right side plate 1, the top plate 3, the left side plate 4 and the bottom plate 26. The plenum chamber 6 is fixed to the rear side of the side-blowing air box, and the filter screen 2 is fixed between the plenum chamber 6 and the side-blowing air box. The filter screen 2 is a honeycomb rectifier plate. The interior of the plenum chamber 6 is connected to the interior of the side-blowing air box through the filter screen 2. The air valve 7 is provided at the bottom of the plenum chamber 6. The air valve 7 controls the amount of cooling air entering the plenum chamber 6.

[0051] The oil rack 8 is a rectangular parallelepiped 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 nozzle slide 24 and the wire guide hook slide 25 are both horizontally arranged in the cavity of the oil rack 8 and parallel to the left and right directions. The nozzle slide 24 is located above the wire guide hook slide 25 and the two are arranged at a distance. The left ends of the nozzle slide 24 and the wire guide hook slide 25 are fixedly connected to the left wall panel of the oil rack 8, and the right ends of the nozzle slide 24 and the wire guide hook slide 25 are fixedly connected to the right wall panel of the oil rack 8. The fixing rod 23 is vertically arranged and is connected to the nozzle slide at the same time. 24 is fixedly connected to the wire guide hook slide 25, the oil nozzle 9 is fixed on the oil nozzle slide 24, the wire guide hook 22 is fixed on the wire guide hook slide 25, the oil nozzle 9 is located above the wire guide hook 22, the function of the fixing rod 23 is to prevent the oil nozzle slide 24 and the wire guide hook slide 25 from deforming and vibrating, and to avoid changes in the positional relationship between the oil nozzle 9 and the wire guide hook 22. The number of fixing rods 23 is determined according to the actual fixing effect, and the number of oil nozzles 9 and wire guide hooks 22 is determined according to the number of silk strips at the spinning position; a first strip hole is provided on the top wall plate of the oil rack 8, and the first strip hole is located directly above the oil nozzle 9;

[0052] The oil rack 8 is arranged horizontally inside the side-blowing bellows; the sliding sleeve 15 is composed of a left sliding sleeve and a right sliding sleeve, the left sliding sleeve is fixed to the front end of the left wall plate of the oil rack 8, and the right sliding sleeve is fixed to the front end of the right wall plate of the oil rack 8, so as to realize the fixed connection between the sliding sleeve 15 and the oil rack 8; the oil rack slide rod 5 is composed of a left oil rack slide rod and a right oil rack slide rod, and the left oil rack slide rod and the right oil rack slide rod are respectively vertically fixed to the left and right sides of the inside of the side-blowing bellows, the left sliding sleeve is sleeved on the left oil rack slide rod and is slidably connected thereto, and the right sliding sleeve is sleeved on the left oil rack slide rod The piston rod of the cylinder 16 is arranged vertically on the right oil rack slide and is slidably connected thereto, 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 of the oil rack 8. A temperature sensor 14 is installed on the top of the oil rack 8 to measure the actual temperature at the top of the oil rack 8. A second strip hole is provided on the top plate 3 of the side-blowing air box. The second strip hole is located directly above the first strip hole. The silk thread passes through the second strip hole and the first strip hole in sequence and enters the oil nozzle 9.

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

[0054] The distance meter 11, the temperature display screen 12, the deviation display screen 13, the temperature sensor 14, and the alarm 19 are all connected to the SMU setter 10; the preset temperature of the top of the oil rack is set by the SMU setter 10, and the theoretical oil rack height is set by the SMU setter 10;

[0055] The first execution controller 17 is connected to the SMU setter 10 and the cylinder 16. The SMU setter 10 controls the flow of compressed air into and out of the cylinder 16 and the elevation of the working end of the piston rod of the cylinder 16 through the first execution controller 17, thereby driving the oil rack 8 to move upward or downward via the sliding sleeve 15 and the oil rack slide rod 5, thereby reducing or increasing the actual height of the oil rack.

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

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

[0058] Example 2

[0059] A method for automatically adjusting wire strip cooling and forming, using the automatic adjustment device for wire strip cooling and forming provided in Example 1, with the following specific steps:

[0060] (1) Set parameters;

[0061] Before the change, the yarn specification was 83dtex / 72f, the actual oil rack height was 800mm, and the cooling air speed was 0.26m / s;

[0062] After the variety change, the melt spinning process is used to produce round bright FDY polyester filament with a specification of 83dtex / 36f (fineness 83dtex, number of spinneret holes 36); in the spinning process, the spinneret diameter d0 is 0.00022m, the temperature t1 of the melt exiting the spinneret is 290℃, the filament is cooled by a side-blowing bellows, the temperature t of the cooling air is 22℃, the glass transition temperature t2 of the filament is 69℃, the winding speed is 5000m / min, the discharge amount G of a single spinneret is 0.069167kg / h, the specific heat capacity C of the melt is 2.2kJ / (kg·℃), and the heat transfer coefficient h is 135kJ / (m 2 ·h·℃), e is 2.718;

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

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

[0065] When the spinning is stopped due to a product change, after entering the above process parameters in the SMU setter, the theoretical oil rack height is calculated according to the following formula:

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

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

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

[0069] The process of automatically adjusting the fuel rack height is as follows: the SMU setter compares the actual fuel rack height measured by the distance meter with (1072mm±100mm); if the actual fuel rack height is < (1072mm-100mm), the fuel rack height is increased until (1072mm-100mm) ≤ actual fuel rack height ≤ (1072mm+100mm); if the actual fuel rack height is > (1072mm+100mm), the fuel rack height is decreased until (1072mm-100mm) ≤ actual fuel rack height ≤ (1072mm+100mm); if (1072mm-100mm) ≤ actual fuel rack height ≤ (1072mm+100mm), the fuel rack height remains unchanged;

[0070] Increasing the height of the oil rack is achieved by the first executive controller controlling the working end of the piston rod of the cylinder to descend, thereby causing the sliding sleeve to move downward along the oil rack slide rod. Reducing the height of the oil rack is achieved by the first executive controller controlling the working end of the piston rod of the cylinder to ascend, thereby causing the sliding sleeve to move upward along the oil rack slide rod.

[0071] When the actual oil rack height is < (1072mm-100mm) or the actual oil rack height is > (1072mm+100mm), the deviation display screen will turn red and the alarm will sound. When (1072mm-100mm)≤actual oil rack height≤(1072mm+100mm), the deviation display screen will return to its normal color and the alarm will be cleared.

[0072] (3) During the spinning process after spinning, the oil rack height 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 of the oil rack top measured by the temperature sensor with (29℃±2℃);

[0074] If the actual temperature at the top of the oil rack is less than (29°C - 2°C), reduce the oil rack height and the cooling air valve opening until (29°C - 2°C) ≤ the actual temperature at the top of the oil rack ≤ (29°C + 2°C), and the cooling air valve opening is set to a minimum value (0%). When the cooling air valve opening 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°C + 2°C), increase the oil rack height and increase the cooling air valve opening until (29°C - 2°C) ≤ the actual temperature at the top of the oil rack ≤ (29°C + 2°C), and the cooling air valve opening is set to the maximum value (100%). When the cooling air valve opening 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℃)≤the actual temperature on the top of the oil rack≤(29℃+2℃), the oil rack height and the cooling air valve opening remain unchanged, and normal spinning continues;

[0077] Increasing the cooling air valve opening is achieved by controlling the second execution controller to increase the cooling air valve opening, and decreasing the cooling air valve opening is achieved by controlling the second execution controller to decrease the cooling air valve opening.

[0078] When the actual temperature of the top of the oil rack is < (29℃-2℃) or the actual temperature of the top of the oil rack is > (29℃+2℃), the deviation display screen will show red and the alarm will sound. When (29℃-2℃) ≤ the actual temperature of the top of the oil rack ≤ (29℃+2℃), the color of the deviation display screen will return to its original normal color and the alarm will be eliminated.

[0079] During the spinning process of this embodiment, the actual oil rack height measured by the rangefinder was 972 mm. The temperature sensor monitored and displayed the actual temperature of the oil rack top in real time on the temperature display. The SMU setter compared the actual temperature of the oil rack top with (the preset temperature of the oil rack top ± the temperature deviation value). The measured actual temperature of the oil rack top was 31.5°C, which exceeded the set range of 29±2°C. The deviation display screen turned red, and the alarm sounded. The data was fed back to the SMU setter, which automatically recognized that the cooling air speed and oil rack height were too low. The first actuator controller then controlled the working end of the piston rod to descend, causing the oil rack to move downward along the oil rack slide rod. Simultaneously, it controlled the second actuator controller to increase the opening of the air valve. When the measured actual temperature of the oil rack top was less than 31°C, the rangefinder measured the actual oil rack height to be 1000 mm. Both the actual height and the actual temperature of the oil rack top were within the set range. The deviation display screen returned to its normal color, and the alarm was cleared, completing the automatic adjustment of the spinning cooling system.

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

[0081] Comparative Example 1

[0082] A method for automatically adjusting the cooling and forming of a filament strip is different from the embodiment 2 only in that the oil rack adopts the automatic height adjustment spinning oil rack provided by the utility model patent announcement number CN222043429U (spinning parameters remain unchanged).

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

[0084] Compared with Example 2, the yarn unevenness CV value of the yarn obtained in Comparative Example 1 increased by 68.1%, the average difference coefficient of yarn unevenness U value increased by 68.1%, and the half inhibition value increased by 50.9%. This is because the yarn specification before the variety change was 83dtex / 72f, the actual oil rack height was 800mm, the cooling air speed was 0.26m / s, the actual oil rack height was small, the oil rack was close to the spinneret, the cooling air speed was low, and the dpf was small (dpf is the denier per filament is the abbreviation of yarn, which refers to the fineness of a single fiber in the yarn). After the variety is changed to 83dtex / 36f, the dpf is significantly increased, and the requirement for the wind speed of the cooling air is also significantly increased. In comparative example 1, the automatic height-adjusting spinning oil rack provided by the utility model with patent announcement number CN222043429U is adopted. The actual oil rack height is adjusted from 800mm to 1072mm, and the wind speed of the cooling air is still 0.26m / s. At this time, the actual temperature at the top of the oil rack is 33℃, which exceeds the set range of 29±2℃. The actual temperature at the top of the oil rack is too high, and the wind speed of the cooling air is too small to meet the cooling requirements of the filament. When the wind speed of the cooling air is too small, on the one hand, the factors of the filament being disturbed by the outdoor air flow are enhanced, and on the other hand, the solidification speed of the filament is slowed down, which increases the factors of the filament floating and vibrating, thereby affecting the uniformity of the filament. The linear density in the length direction after forming is uneven, the final measured unevenness of the filament is large, and the dyeing is slightly uneven.

[0085] Comparative Example 2

[0086] A method for automatically adjusting wire strip cooling and forming, which differs from Example 2 only in that the empirical constant is 1.

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

[0088] Compared with Example 2, the CV value of the yarn unevenness rate of the yarn obtained in Comparative Example 2 increased by 125.3%, the U value of the average difference coefficient of yarn unevenness increased by 126.4%, and the half-inhibition value increased by 84.2%. This is because the specification of the yarn before the variety change was 83dtex / 72f, the actual oil rack height was 800mm, the cooling air speed was 0.26m / s, the actual oil rack height was small, the oil rack was close to the spinneret, the cooling air speed was low, and the dpf was small. After the variety was changed to 83dtex / 36f, the dpf increased significantly, and the requirement for the cooling air speed was also significantly increased. The empirical constant of Comparative Example 2 was 1, and the calculated theoretical oil rack height was 536mm. The setting range of the oil rack height was 436-636mm, which was smaller than the actual oil rack height of 800mm before the variety change. When the actual oil rack height was adjusted to the range of 436-636mm, the actual temperature at the top of the oil rack was >40°C. , exceeding the set range of 29±2℃, it is necessary to continuously increase the opening of the cooling air valve to make the air valve opening reach the maximum value of 100%. At this time, the wind speed of the cooling air is 0.9m / s, the silk strips are in a sudden cooling state, the internal and external structures are inconsistent, and they are formed into a skin-core structure; when the wind speed of the cooling air is too large, the turbulence factor increases, and any turbulence of the air flow will inevitably cause the silk strips to vibrate or flutter. When the vibration amplitude reaches a certain value, it will be transmitted to the top of the coagulation zone, causing the linear density of the silk strips in the length direction to be seriously uneven. The measured unevenness of the strips is seriously too large, the dyeing is seriously striped, and the dyeing is uneven, which is an unqualified 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 of the strips, which has an adverse effect on product quality.

[0089] Example 3

[0090] A method for automatically adjusting wire strip cooling and forming, using the automatic adjustment device for wire strip cooling and forming provided in Example 1, with the following specific steps:

[0091] (1) Set parameters;

[0092] Before the change, the yarn specification was 83dtex / 36f, the actual oil rack height was 1050mm, and the cooling air speed was 0.4m / s;

[0093] After the variety change, the melt spinning process was adopted to produce round bright FDY polyester filament with a specification of 111dtex / 36f (fineness 111dtex, number of spinneret holes 36); in the spinning process, the spinneret diameter d0 was 0.00022m, the temperature t1 of the melt exiting the spinneret was 290℃, the filaments were cooled by a side-blowing bellows, the temperature t of the cooling air was 22℃, the wind speed of the cooling air was 0.45m / s, the glass transition temperature t2 of the filaments was 69℃, the winding speed was 5000m / min, the discharge amount G of a single spinneret was 0.0925kg / h, the specific heat capacity C of the melt was 2.2kJ / (kg·℃), and the heat transfer coefficient h was 135kJ / (m 2 ·h·℃), e is 2.718;

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

[0095] (2) When the spinning stop is changed, the theoretical oil rack height is automatically calculated and the oil rack height is automatically adjusted;

[0096] When changing the spinning stop, after entering the above process parameters in 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 unit of curing distance is mm;

[0099] Theoretical oil rack height = 1.5× × × ×1000=1075mm;

[0100] The process of automatically adjusting the fuel rack height is as follows: the SMU setter compares the actual fuel rack height measured by the distance meter with (1075mm±100mm); if the actual fuel rack height is < (1075mm-100mm), the fuel rack height is increased until (1075mm-100mm) ≤ actual fuel rack height ≤ (1075mm+100mm); if the actual fuel rack height is > (1075mm+100mm), the fuel rack height is decreased until (1075mm-100mm) ≤ actual fuel rack height ≤ (1075mm+100mm); if (1075mm-100mm) ≤ actual fuel rack height ≤ (1075mm+100mm), the fuel rack height remains unchanged;

[0101] Increasing the height of the oil rack is achieved by the first executive controller controlling the working end of the piston rod of the cylinder to descend, thereby causing the sliding sleeve to move downward along the oil rack slide rod. Reducing the height of the oil rack is achieved by the first executive controller controlling the working end of the piston rod of the cylinder to ascend, thereby causing the sliding sleeve to move upward along the oil rack slide rod.

[0102] When the actual oil rack height is < (1075mm-100mm) or the actual oil rack height is > (1075mm+100mm), the deviation display screen will turn red and the alarm will sound. When (1075mm-100mm)≤actual oil rack height≤(1075mm+100mm), the deviation display screen will return to its normal color and the alarm will be cleared.

[0103] (3) During the spinning process after spinning, the oil rack height 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 of the oil rack top measured by the temperature sensor with (30℃±2℃);

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

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

[0108] Increasing the cooling air valve opening is achieved by controlling the second execution controller to increase the cooling air valve opening, and decreasing the cooling air valve opening is achieved by controlling the second execution controller to decrease the cooling air valve opening.

[0109] When the actual temperature of the top of the oil rack is < (30℃-2℃) or the actual temperature of the top of the oil rack is > (30℃+2℃), the deviation display screen will show red and the alarm will sound. When (30℃-2℃) ≤ the actual temperature of the top of the oil rack ≤ (30℃+2℃), the color of the deviation display screen will return to its original normal color and the alarm will be eliminated.

[0110] During the spinning process of this embodiment, the actual oil rack height measured by the rangefinder is 1120 mm, which is within the range of 975-1175 mm. At this time, the temperature sensor monitors and displays the actual temperature of the oil rack top on the temperature display in real time. The SMU setter compares the actual temperature of the oil rack top with (the preset temperature of the oil rack top ± the temperature deviation value) and measures that the actual temperature of the oil rack top is 33°C, which exceeds the set range of 30±2°C. The deviation display turns red, the alarm sounds, and the data is fed back to the SMU setter. The SMU setter automatically recognizes that the actual temperature of the oil rack top exceeds the set range and determines that the cooling air speed and the actual oil rack height are too low. At this time, the first execution controller controls the working end of the piston rod of the cylinder to descend, causing the oil rack to move downward along the oil rack slide rod. At the same time, the second execution controller increases the opening of the cooling air valve to increase the cooling air speed.

[0111] When the actual oil rack height measured by the rangefinder is greater than 1175mm, the temperature display screen shows in real time that the actual temperature of the top of the oil rack is 32.6℃, which is still beyond the set range of 30±2℃. At this time, the deviation display screen shows red, and the alarm continues to prompt abnormality. After shutdown and inspection, it was found that the filter in the pressure stabilizing chamber was clogged. As the opening of the air valve increased, the wind speed did not change, and the actual temperature of the top of the oil rack did not change. After replacing the filter, the temperature display screen showed in real time that the actual temperature of the top of the oil rack was 27℃, which exceeded the set range of 30±2℃. At this time, the first execution controller controls the working end of the piston rod of the cylinder to rise, so that the oil rack moves upward along the oil rack slide rod. At the same time, the second execution controller reduces the opening of the cooling air valve and reduces the wind speed. Finally, the rangefinder measures the actual oil rack height as 1100mm, and the actual temperature of the top of the oil rack monitored by the temperature sensor and displayed on the temperature display screen is 28.9℃. The color of the deviation display screen returns to normal, and the alarm is eliminated.

[0112] The CV value of the yarn unevenness rate of the yarn prepared in Example 3 is 0.92%, the U value of the average difference coefficient of yarn unevenness is 0.72%, and the half inhibition value is 0.47% (the test conditions for the CV value of the yarn unevenness rate, the U value of the average difference coefficient of yarn unevenness and the half inhibition value are: test speed of 400 m / min, test time of 1 min, measuring groove width of 0.36 mm, twister: S twist, twisting speed of 21000 r / min, nominal count 111 dtex / 36f), and the dyeing evenness is level 4.5.

[0113] Comparative Example 3

[0114] A method for automatically adjusting the cooling and forming of a yarn, which differs from Example 3 only in that the empirical constant is 1.

[0115] The final yarn has a CV value of 2.16% for unevenness, a U value of 1.73% for average unevenness, and a half-suppression value of 1.1% (the test conditions for the CV value of unevenness, the U value of average unevenness, and the half-suppression value are: a test speed of 400 m / min, a test time of 1 min, a measuring slot width of 0.36 mm, a twister: S twist, a twisting speed of 21000 r / min, and a nominal count of 111 dtex / 36 f), and a dyeing uniformity of 3.0 levels.

[0116] Compared with Example 3, the CV value of unevenness of the yarn produced in Comparative Example 3 increases by 134.8%, the U value of average unevenness increases by 140.3%, and the half-suppression value increases by 134.0%. This is because when the variety specification is changed from 83 dtex / 36 f to 111 dtex / 36 f, dpf increases, and the air volume requirement for cooling air also significantly increases. The empirical constant of Comparative Example 3 is 1, the calculated theoretical oil rack height is 717 mm, the set range of the oil rack height is 617-817 mm, and the set range is less than the actual oil rack height of 1050 mm before the variety 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 of 30±2°C. The opening degree of the cooling air valve needs to be continuously opened to make the cooling air speed reach 0.8 m / s. At this time, the cooling air speed is too large, the turbulence factor increases, and any turbulence of air flow will cause the yarn to vibrate or drift. When the vibration amplitude reaches a certain value, it will be transmitted to the upper part of the solidification zone, causing the linear density of the yarn in the length direction to be seriously uneven. The measured unevenness is seriously biased, the dyeing has serious stripes, the dyeing is uneven, and it is a substandard product. This shows that when the empirical constant is 1, the empirical constant is too small, which will lead to an increase in unevenness and have an adverse effect on product quality.

[0117] Example 4

[0118] A method for automatically adjusting the cooling and forming of a yarn, which adopts the yarn cooling and forming automatic adjustment device provided in Example 1, and the specific steps are as follows:

[0119] (1) Set the parameters;

[0120] The specification of the yarn before the variety change is 83 dtex / 36 f, the actual oil rack height is 1050 mm, and the cooling air speed is 0.4 m / s;

[0121] After the variety change, the melt spinning process is used to produce round bright FDY polyester filament with a specification of 83dtex / 72f (fineness 83dtex, number of spinneret holes 72); in the spinning process, the spinneret diameter d0 is 0.00016m, the temperature t1 of the melt exiting the spinneret is 290℃, the filaments are cooled by a side-blowing bellows, the temperature t of the cooling air is 22℃, the wind speed of the cooling air is 0.26m / s, the glass transition temperature t2 of the filaments is 69℃, the winding speed is 5000m / min, the discharge amount G of a single spinneret is 0.0346kg / h, the specific heat capacity C of the melt is 2.2kJ / (kg·℃), and the heat transfer coefficient h is 135kJ / (m 2 ·h·℃), e is 2.718;

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

[0123] (2) When the spinning stop is changed, the theoretical oil rack height is automatically calculated and the oil rack height is automatically adjusted;

[0124] When the spinning is stopped due to product changes, after entering the above process parameters in 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 unit of curing distance is mm;

[0127] Theoretical oil rack height = 2.5× × × ×1000=921mm;

[0128] The process of automatically adjusting the fuel rack height is as follows: the SMU setter compares the actual fuel rack height measured by the distance meter with (921mm±50mm); if the actual fuel rack height is < (921mm-50mm), the fuel rack height is increased until (921mm-50mm) ≤ actual fuel rack height ≤ (921mm+50mm); if the actual fuel rack height is > (921mm+50mm), the fuel rack height is decreased until (921mm-50mm) ≤ actual fuel rack height ≤ (921mm+50mm); if (921mm-50mm) ≤ actual fuel rack height ≤ (921mm+50mm), the fuel rack height remains unchanged;

[0129] Increasing the height of the oil rack is achieved by the first executive controller controlling the working end of the piston rod of the cylinder to descend, thereby causing the sliding sleeve to move downward along the oil rack slide rod. Reducing the height of the oil rack is achieved by the first executive controller controlling the working end of the piston rod of the cylinder to ascend, thereby causing the sliding sleeve to move upward along the oil rack slide rod.

[0130] When the actual oil rack height is < (921mm-50mm) or the actual oil rack height is > (921mm+50mm), the deviation display screen will show red and the alarm will sound. When (921mm-50mm)≤actual oil rack height≤(921mm+50mm), the color of the deviation display screen will return to its original normal color and the alarm will be cleared.

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

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

[0133] If the actual temperature at the top of the oil rack is less than (30°C - 1°C), reduce the oil rack height and the cooling air valve opening until (30°C - 1°C) ≤ the actual temperature at the top of the oil rack ≤ (30°C + 1°C), and the cooling air valve opening is set to a minimum value (0%). When the cooling air valve opening 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 > (30°C + 1°C), increase the oil rack height and increase the cooling air valve opening until (30°C - 1°C) ≤ the actual temperature at the top of the oil rack ≤ (30°C + 1°C), and the cooling air valve opening is set to the maximum value (100%). When the cooling air valve opening reaches the maximum value, if the actual oil rack height is > (921mm + 50mm) or the actual oil rack height is < (921mm - 50mm), stop the machine and check the cooling air supply system.

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

[0136] Increasing the cooling air valve opening is achieved by controlling the second execution controller to increase the cooling air valve opening, and decreasing the cooling air valve opening is achieved by controlling the second execution controller to decrease the cooling air valve opening.

[0137] When the actual temperature of the top of the oil rack is < (30℃-1℃) or the actual temperature of the top of the oil rack is > (30℃+1℃), the deviation display screen will show red and the alarm will sound. When (30℃-1℃) ≤ the actual temperature of the top of the oil rack ≤ (30℃+1℃), the color of the deviation display screen will return to its original normal color and the alarm will be eliminated.

[0138] In this embodiment, during the spinning process, the actual oil rack height measured by the rangefinder is 950 mm, which is within the range of 871-971 mm. At this time, the temperature sensor monitors the actual temperature of the oil rack top in real time and displays it on the temperature display. The SMU setter compares the actual temperature of the oil rack top with (the preset temperature of the oil rack top ± the temperature deviation value). The measured actual temperature of the oil rack top is 28.5°C, which exceeds the set range of 30±1°C. The deviation display turns red, the alarm sounds, and the data is fed back to the SMU setter, which automatically identifies the actual temperature of the oil rack top. The temperature exceeds the set range, and it is judged that the wind speed of the cooling air is too high and the actual oil rack height is too high. At this time, the first execution controller controls the working end of the piston rod of the cylinder to rise, so that the oil rack moves upward along the oil rack slide rod. At the same time, the second execution controller reduces the opening of the cooling air valve and reduces the wind speed. When the actual temperature of the top of the oil rack reaches 29-31℃, the actual oil rack height measured by the rangefinder is 920mm. At this time, the actual oil rack height and the actual temperature of the top of the oil rack are both within the set range. The color of the deviation display screen returns to normal, the alarm is eliminated, and the automatic adjustment of the spinning cooling system is completed.

[0139] The CV value of the yarn unevenness rate of the yarn prepared in Example 4 is 1.01%, the U value of the average difference coefficient of yarn unevenness is 0.81%, and the half inhibition value is 0.69% (the test conditions for the CV value of the yarn unevenness rate, the U value of the average difference coefficient of yarn unevenness and the half inhibition value are: test speed of 400 m / min, test time of 1 min, measuring slot width of 0.36 mm, twister: S twist, twisting speed of 22000 r / min, nominal count 83 dtex / 72f), and the dyeing evenness is level 4.5.

[0140] Comparative Example 4

[0141] A method for automatically adjusting wire strip cooling and forming, which differs from Example 4 only in that the empirical constant is 3.

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

[0143] Compared with Example 4, the CV value of the yarn unevenness rate of the yarn obtained in Comparative Example 4 increased by 67.3%, the U value of the average difference coefficient of yarn unevenness increased by 64.2%, and the half inhibition value increased by 34.8%. This is because the specification of the yarn before the variety change was 83dtex / 36f, the actual oil rack height was 1050mm, the wind speed of the cooling air was 0.4m / s, the actual oil rack height was large, the oil rack was far away from the spinneret, the wind speed of the cooling air was moderate, and the dpf was large. After changing to 83dtex / 72f, the dpf was significantly reduced, and the requirement for the wind speed of the cooling air was also significantly reduced. The empirical constant of Comparative Example 4 is 3, the calculated theoretical oil rack height is 1106mm, and the setting range of the oil rack height is 1056-1156mm. This setting range is greater than the actual oil rack height of 1050mm before the change. The actual oil rack height is adjusted to 1056-1156 mm range, the actual temperature at the top of the oil rack is <27℃, which exceeds the set range of 30±1℃. It is necessary to continuously reduce the opening of the cooling air valve until the cooling air speed is 0.1m / s. When the cooling air speed is too small, on the one hand, the silk strips are more susceptible to interference from outdoor airflow, and on the other hand, the silk strip solidification speed slows down, which increases the factors of silk strip fluttering and vibration, thereby affecting the uniformity of the silk strips. 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 of the silk strips, which has an adverse effect on product quality.

Claims

1. A method for automatically adjusting the cooling and forming of a yarn, comprising the step of stopping spinning to change the variety, characterized in that: When spinning is stopped to change the product type, the following steps are also performed: Calculate the theoretical oil rack height of the changed product and measure the actual oil rack height; Compare the actual oil rack height with the theoretical oil rack height ± height deviation value; If the actual fuel rack height is less than the theoretical fuel rack height - height deviation value, increase the fuel rack height until the theoretical fuel rack height - height deviation value ≤ actual fuel rack height ≤ theoretical fuel rack height + height deviation value; If the actual fuel rack height is greater than the theoretical fuel rack height + height deviation value, reduce the fuel rack height until the theoretical fuel rack height - height deviation value ≤ actual fuel rack height ≤ theoretical fuel rack height + height deviation value; If the theoretical oil rack height - height deviation value ≤ actual oil rack height ≤ theoretical oil rack height + height deviation value, the oil rack height remains unchanged; The calculation formula of theoretical oil rack height is as follows: Theoretical oil rack height = empirical constant × curing distance; the empirical constant value range is 1.5-2.5; Curing distance × × ×1000, the unit of curing distance is mm; Where d0 is the diameter of the spinneret, in m; t1 is the temperature of the melt exiting the spinneret, in °C; t2 is the glass transition temperature of the filament, in °C; t is the temperature of the cooling air, in °C; G is the discharge rate of a single spinneret, in kg / h; C is the specific heat capacity of the melt, in kJ / (kg·°C); h is the heat transfer coefficient, which is fixed at 135 kJ / (m 2 ·h·℃); e is the base of the natural logarithm, which has a fixed value of 2.

718.

2. A method for automatically adjusting wire strip cooling and forming according to claim 1, characterized in that: As the empirical constant changes in the range of 1.5-2.5, the CV value of the strand unevenness of the cooled silk strip is tested. When the CV value of the strand unevenness is the smallest, the corresponding empirical constant value is the optimal empirical constant value.

3. The method for automatically adjusting the cooling and forming of a wire strip according to claim 1, characterized in that: The calculation of the theoretical fuel rack height of the changed variety is completed by the SMU setter, the measurement of the actual fuel rack height is completed by the distance meter, and the comparison of the actual fuel rack height with the theoretical fuel rack height ± the height deviation value is completed by the SMU setter.

4. The method for automatically adjusting the cooling and forming of a wire strip according to claim 1, wherein: The height deviation value is 50-100mm.

5. The method for automatically adjusting the cooling and forming of a wire strip according to claim 1, wherein: It also includes the spinning process after the variety change; During the spinning process, the temperature of the top of the oil rack is set to a preset temperature, and the actual temperature of the top of the oil rack is monitored in real time. The actual temperature of the top of the oil rack is compared with the preset temperature of the top of the oil rack ± the temperature deviation value; the preset temperature is 25-30℃, and the temperature deviation value is 1-2℃; If the actual temperature of the oil rack top is less than the preset temperature of the oil rack top - the temperature deviation value, the oil rack height is reduced, and at the same time, the cooling air valve opening is reduced until the preset temperature of the oil rack top - the temperature deviation value ≤ the actual temperature of the oil rack top ≤ the preset temperature of the oil rack top + the temperature deviation value, and the cooling air valve opening is set with a minimum value. When the cooling air valve opening reaches the minimum value, if the actual oil rack height is greater than the theoretical oil rack height + the height deviation value or the actual oil rack height is less than the theoretical oil rack height - the height deviation value, the machine is shut down to check the cooling air supply system; If the actual temperature of the oil rack top is greater than the preset temperature of the oil rack top + the temperature deviation value, the oil rack height is increased, and at the same time, the cooling air valve opening is increased until the preset temperature of the oil rack top - the temperature deviation value ≤ the actual temperature of the oil rack top ≤ the preset temperature of the oil rack top + the temperature deviation value, and the cooling air valve opening is set to a maximum value. When the cooling air valve opening reaches the maximum value, if the actual oil rack height is greater than the theoretical oil rack height + the height deviation value or the actual oil rack height is less than the theoretical oil rack height - the height deviation value, the machine is shut down to check the cooling air supply system; If the preset temperature of the oil rack top - temperature deviation value ≤ actual temperature of the oil rack top ≤ preset temperature of the oil rack top + temperature deviation value, the oil rack height and the cooling air valve opening remain unchanged and normal spinning continues.

6. A method for automatically adjusting wire strip cooling and forming according to claim 5, characterized in that: As the empirical constant changes in the range of 1.5-2.5 and the preset temperature changes in the range of 25-30℃, the CV value of the strand unevenness of the cooled silk strips is tested. When the CV value of the strand unevenness reaches the minimum, the corresponding empirical constant value is the optimal empirical constant value, and the corresponding preset temperature is the optimal preset temperature.

7. A method for automatically adjusting wire strip cooling and forming according to claim 5, characterized in that: 0%<The cooling air valve opening is ≤100%.

8. The method for automatically adjusting the cooling and forming of a wire strip according to claim 5, characterized in that: The preset temperature setting for the temperature of the top of the oil rack is completed through the SMU setter, and the real-time monitoring of the actual temperature of the top of the oil rack is completed through the temperature sensor. The temperature sensor is installed on the top of the oil rack, and the actual temperature of the top of the oil rack is compared with the preset temperature of the top of the oil rack ± the temperature deviation value through the SMU setter.

9. The method for automatically adjusting the cooling and forming of a wire strip according to claim 5, characterized in that: The increase and decrease of the opening of the cooling air damper are completed through the SMU setter and the second execution controller, and the second execution controller is connected to the SMU setter and the cooling air damper at the same time.

10. A method for automatically adjusting wire strip cooling and forming according to any one of claims 1 to 9, characterized in that: Increasing and decreasing the height of the oil rack are completed through the SMU setter, the first executive controller, the cylinder, the oil rack slide rod and the sliding sleeve. The sliding sleeve is fixed on the side of the oil rack, the oil rack slide rod is fixed vertically, and the sliding sleeve is slid up and down on the oil rack slide rod. The working end of the cylinder piston rod is fixedly connected to the bottom of the oil rack. The first executive controller is connected to the SMU setter and the cylinder at the same time. The SMU setter controls the working end of the cylinder piston rod and the oil rack to move upward or downward through the first executive controller, thereby reducing or increasing the height of the oil rack respectively.

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