A spinning air box

Abstract

This utility model discloses a spinning air box, including a box body and guide plates. Two guide plates are symmetrically installed on the inner side of the box body, forming a cooling air channel. Polyester fibers pass vertically through the cooling air channel from top to bottom. The two guide plates form two symmetrically arranged air chamber spaces inside the box body. A horizontally placed partition is fixedly installed in the air chamber space, dividing the air chamber space into several partitioned air chambers along the height direction. Each partitioned air chamber is equipped with an air inlet control device. The surface of the guide plates has ventilation slots. This utility model divides the cooling air channel into multiple areas along the fiber's forward direction, creating a gradient cooling effect. This helps improve the uniformity of internal and external crystallization of the polyester fiber and enhances the mechanical strength of the finished fiber. This utility model adopts a tapered design for the cooling air channel to improve the air pressure balance within the cooling air channel, which helps reduce air volume and lower production energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of polyester fiber spinning technology, and more specifically, to a spinning bellows. Background Technology

[0002] Currently, the polyester fiber spinning process commonly uses side-blowing (or annular) single-temperature-field cooling technology to cool the polyester melt stream (forming polyester fibers). While this achieves basic curing, insufficient uniformity of cooling rate leads to significant differences in crystallinity between the inner and outer layers of the fiber. (In a single-temperature-field windbox, the cooling air temperature is uniform, and to ensure cooling effect, the air temperature is set low while the air volume is large. During the curing process, there is a large temperature difference between the surface and core layers of the ester melt stream. The surface layer directly contacts the cooling air, cools down and solidifies rapidly, forming a highly crystalline hard shell. The core layer, however, experiences delayed heat transfer, cools slowly, has lower crystallinity, and insufficient molecular chain orientation.) The cooled fibers are prone to problems such as internal stress concentration and high fiber breakage rate. The single-temperature-field cooling technology also has the problems of significant air volume waste and high production energy consumption. Therefore, enterprises urgently need to improve and design new spinning windbox devices to meet production needs. The new spinning windbox devices need to improve fiber mechanical properties and reduce production energy consumption. Utility Model Content

[0003] The purpose of this invention is to address the needs of the prior art and provide a spinning air box. This invention divides the cooling air duct into multiple regions along the fiber's forward direction, creating a gradient cooling effect. This helps improve the uniformity of internal and external crystallization of polyester fibers and enhances the mechanical strength of the finished fibers. This invention adopts a tapered design for the cooling air duct to improve the air pressure balance within the cooling air duct, which helps reduce air volume consumption and lower production energy consumption.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A spinning air box includes a box body and two guide plates. Two guide plates are symmetrically installed on the inner side of the box body, forming a cooling air duct. Polyester fibers pass vertically through the cooling air duct from top to bottom. The two guide plates form two symmetrically arranged air chambers inside the box body. A horizontally placed partition is fixedly installed in the air chamber, which divides the air chamber into several partitioned air chambers along the height direction. Each partitioned air chamber is equipped with an air inlet control device. The surface of the guide plate has ventilation slots, which connect the air chambers and the cooling air duct.

[0006] Furthermore, several air inlets are installed on the side of the housing, and each air inlet corresponds to a zoned air chamber.

[0007] Furthermore, the air intake control device includes an induced draft fan, which is fixedly installed in the partitioned air chamber. The air intake end of the induced draft fan is connected to the air intake pipe, and the air outlet end of the induced draft fan is equipped with a temperature control element.

[0008] Furthermore, the temperature control element includes an electric heater and a micro-cooling plate, wherein the electric heater and the micro-cooling plate are not turned on simultaneously.

[0009] Furthermore, several temperature sensors are installed on the inner wall of the cooling duct, and each temperature sensor is set to correspond to a polyester fiber.

[0010] Furthermore, the guide plate is installed at an angle, and the cooling air duct forms a downwardly tapering structure.

[0011] Furthermore, the ventilation slots on the guide plate are horizontal slots, and the ventilation slots are evenly distributed along the height direction of the guide plate.

[0012] Furthermore, the coverage area of ​​the ventilation slot is greater than 60% of the cross-sectional area of ​​its corresponding zone air cavity in the height direction.

[0013] The beneficial effects of this utility model are:

[0014] 1. This utility model divides the cooling air duct into regions along the fiber's forward direction, and each region is equipped with a set of air intake control devices to adjust the air intake temperature and air intake speed, thereby creating a gradient cooling effect. This will help improve the internal and external crystallization uniformity of polyester fibers and enhance the mechanical strength of the finished fibers.

[0015] 2. This utility model forms a gradually narrowing cooling air duct through two guide plates. This design can improve the air pressure balance in the cooling air duct and significantly improve the uniformity of wind speed distribution around the fiber, which helps to reduce air volume and reduce production energy consumption. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the internal structure of a spinning bellows in this embodiment;

[0017] Figure 2 for Figure 1 Sectional view along line AA in the middle;

[0018] Figure 3 This is a front view of the guide plate in this embodiment.

[0019] Reference numerals: 1. Housing; 11. Air inlet; 12. Temperature sensor; 2. Guide plate; 21. Ventilation slot; 3. Cooling duct; 4. Air cavity space; 41. Partition plate; 42. Zoned air cavity; 5. Air intake control device; 51. Exhaust fan; 52. Temperature control element; 521. Electric heater; 522. Miniature cooling plate. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] like Figures 1-3 The spinning air box shown includes a box body 1 and two guide plates 2. Two guide plates 2 are symmetrically installed inside the box body 1, forming a cooling air duct 3. A spinneret is installed at the top of the cooling air duct 3, and the spinneret sprays out fine streams of polyester melt. The polyester melt streams are cooled to form polyester fibers, which pass vertically from top to bottom through the cooling air duct 3. The lower end of the cooling air duct 3 is open, forming a top-to-bottom airflow path within the cooling air duct 3. The two guide plates 2 form two symmetrically arranged air chamber spaces 4 inside the box body 1. Arranged on the left and right sides of the cooling air duct 3, horizontally placed partitions 41 are fixedly installed in the air cavity space 4, dividing the air cavity space 4 into several partitioned air cavities 42 along the height direction. Each partitioned air cavity 42 is equipped with an air intake control device 5. The surface of the guide plate 2 has ventilation slots 21, which connect the air cavity space 4 and the cooling air duct 3. Two partitioned air cavities 42 at the same height form a group. Each group of partitioned air cavities 42 is controlled by the air intake control device 5 installed inside to determine the air intake temperature. The change in inlet air velocity is determined based on actual operating conditions. Preferably, three partitioned air chambers 42 are set along the height of the air chamber space 4. This creates three zones along the cooling air duct 3 from top to bottom (each zone corresponds to a set of partitioned air chambers 42), designated as a high-temperature zone, a medium-temperature zone, and a low-temperature zone (high-temperature zone set at 80-100℃, medium-temperature zone at 50-70℃, and low-temperature zone at 20-40℃). The polyester melt stream first passes through the high-temperature zone after exiting the spinneret, where the air temperature is higher. It can both cool the fine flow of ester melt and prevent the surface from becoming overcooled. The cooling rates of the surface and core layers are matched, improving the uniformity of cooling. The same applies to the medium and low temperature zones. The step-down cooling from top to bottom through the cooling air duct 3 can effectively and gradually control the surface cooling rate of the polyester fiber, matching the cooling rate of the surface and core layers. The uniformity of the cooling rate is significantly improved. This will help improve the internal and external crystallization uniformity of the polyester fiber, enhance the mechanical strength of the finished fiber, and solve the problem of high fiber breakage rate when using conventional air boxes.

[0022] The cooling air of this invention is drawn in from the outside of the air box, therefore... Figure 1As shown, several air inlets 11 are installed on the side of the housing 1. Because each zone air chamber 42 is equipped with an independent air intake control device 5, the air inlets 11 are set up one-to-one with the zone air chambers 42, as shown. Figure 1 As shown, the air intake control device 5 includes an induced draft fan 51, which is an axial flow fan. The induced draft fan 51 is fixedly installed in the partitioned air chamber 42. The air inlet end of the induced draft fan 51 is connected to the air inlet pipe 11, and the air outlet end of the induced draft fan 51 is equipped with a temperature control element 52. The induced draft fan 51 can control the wind speed and air intake volume, and the temperature control element 52 can control the air temperature entering the partitioned air chamber 42. The temperature control element 52 includes an electric heater 521 and a miniature cooling fin 522. The electric heater 521 and the miniature cooling fin 522 are commercially available equipment. This is existing technology, so the structure will not be described in detail here. The electric heater 521 has a heating and air intake function (heating up), and the miniature cooling plate 522 is a semiconductor refrigeration plate with a cooling and air intake function (utilizing the Peltier effect, absorbing heat and cooling down when reverse current is applied). The electric heater 521 and the miniature cooling plate 522 have the advantages of fast response speed (seconds) and high accuracy (±1℃), making them suitable for use. The electric heater 521 and the miniature cooling plate 522 do not operate simultaneously; their operation is determined by measuring the surface temperature of the polyester fiber. Figure 2 As shown, several temperature sensors 12 are installed on the inner wall of the cooling duct 3. Each temperature sensor 12 corresponds to a polyester fiber. The temperature sensors 12 are infrared temperature sensors, measuring the surface temperature of the fiber filaments (because infrared light cannot penetrate the fiber interior). The temperature values ​​measured by the temperature sensors 12 are used to calculate and control the activation of the temperature control element 52. For example, if the low-temperature zone of the cooling duct 3 is set to have a fiber surface temperature of 30±2℃, and the actual temperature measured by the temperature sensor 12 is 28℃ (lower than the set target), it indicates that the air intake of the cooling duct 3 is too cold, requiring heating of the intake air and a reduction in airflow speed. This reduces heat loss from the fiber surface and brings the temperature back to the set target. If the temperature sensor 12 measures an actual temperature of 34℃ (higher than the set target), then... It is proven that the air intake of cooling duct 3 is overheated, requiring cooling of the intake air and an increase in air velocity to enhance convective heat transfer and reduce the temperature of the fiber surface. In actual production, the air velocity in the high-temperature zone, medium-temperature zone, and low-temperature zone should be set to gradually increase. This is because the slower the air velocity, the slower the cooling rate of the fiber surface. The high-temperature zone inherently requires the slowest cooling rate, so the air velocity should be set to be slower (the air velocity is determined by the induced draft fan 51). In actual production, there are also situations where the spinning speed increases. As the spinning speed increases, the cooling time of the fiber through cooling duct 3 is shortened, and the temperature of the fiber surface will rise. At this time, it is necessary to simultaneously increase the air velocity in the high-temperature zone, medium-temperature zone, and low-temperature zone (generally by 0.3 m / s according to the change in spinning speed) to compensate for the shortened cooling time.

[0023] Conventional air boxes use a straight cylindrical air duct. To ensure effective cooling of all fibers, conventional air boxes increase the cooling air intake, but this results in significant air waste and higher energy consumption during operation. Figure 2 As shown, this utility model changes the structural design of the cooling air duct 3. The guide plate 2 is installed at an angle, and the ventilation slots 21 on the guide plate 2 are horizontal slots. The ventilation slots 21 are evenly distributed along the height direction of the guide plate 2. Cooling air first fills the partitioned air chamber 42, and then enters the cooling air duct through the ventilation slots 21. The cooling air is vertically blown onto the fiber surface. With the two guide plates 2 symmetrically tilted, the cooling air duct 3 forms a downwardly tapering structure. The cooling air duct 3 gradually contracts along the fiber's forward direction, which will create two effects: an airflow acceleration effect: according to Bernoulli's equation, the reduction in cross-section accelerates the airflow. Increased kinetic energy; static pressure equalization effect: the reduced static pressure of the accelerated airflow allows for automatic pressure balance at various points in the cooling duct 3, preventing localized eddies. This significantly improves the uniformity of airflow distribution around each fiber, reaching >95% (compared to only 70%~80% in conventional straight-tube air boxes). This design enhances airflow assurance for each fiber, reduces air consumption, and, combined with the reduced air consumption from the gradient temperature zone design, significantly improves airflow waste in the entire air box, greatly reducing ineffective airflow. Overall energy consumption is reduced by 15%-25% compared to conventional air boxes. Figure 3 As shown, the coverage area of ​​the ventilation slot 21 is greater than 60% of the cross-sectional area of ​​its corresponding partition air cavity 42 in the height direction. This is to ensure smooth airflow at the position of the guide plate 2. Currently, the company sets the width of the ventilation slot 21 to 0.5mm and the spacing to 5mm.

[0024] Example:

[0025] This invention can be used to produce high-strength PET industrial yarn.

[0026] Process parameters:

[0027] Melt temperature: 290℃; Spinning speed: 3500 m / min

[0028] Gradient cooling parameters:

[0029] Cooling duct 3, high-temperature zone: air temperature 90℃, air velocity 1.2 m / s;

[0030] Cooling duct 3, medium temperature zone: air temperature 60℃, air velocity 1.8 m / s;

[0031] Cooling duct 3, low-temperature zone: air temperature 30℃, air velocity 2.0 m / s

[0032] Implementation results:

[0033] Fiber breaking strength is increased by 15% (compared to traditional cooling processes); the breakage rate is reduced to below 0.5%; and the energy consumption of the cooling system is reduced by 20%.

[0034] By optimizing the fiber crystal structure through gradient cooling, the tensile strength is ≥8.5 cN / dtex, which is superior to that of conventional processes (7.0-7.5 cN / dtex). Overall energy consumption is reduced by 15%-25%.

[0035] This invention can also be adapted to the production of polyester fibers of different specifications (such as fine denier yarn and industrial yarn) by adjusting gradient parameters.

[0036] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A spinning bellows, characterized in that, Includes a housing (1) and a guide plate (2). Two guide plates (2) are symmetrically installed inside the housing (1). The two guide plates (2) form a cooling air duct (3). Polyester fibers pass vertically from top to bottom through the cooling air duct (3). The two guide plates (2) form two symmetrically arranged air cavity spaces (4) inside the housing (1). A horizontally placed partition (41) is fixedly installed in the air cavity space (4). The partition (41) divides the air cavity space (4) into several partitioned air cavities (42) along the height direction. Each partitioned air cavity (42) is equipped with an air intake control device (5). The surface of the guide plate (2) is provided with a ventilation groove (21). The ventilation groove (21) connects the air cavity space (4) and the cooling air duct (3).

2. The spinning bellows according to claim 1, characterized in that, The side of the housing (1) is equipped with several air inlets (11), and the air inlets (11) are set one-to-one with the partitioned air chambers (42).

3. The spinning bellows according to claim 2, characterized in that, The air intake control device (5) includes an exhaust fan (51), which is fixedly installed in the partitioned air chamber (42). The air intake end of the exhaust fan (51) is connected to the air intake port (11), and the air outlet end of the exhaust fan (51) is equipped with a temperature control element (52).

4. The spinning bellows according to claim 3, characterized in that, The temperature control element (52) includes an electric heater (521) and a miniature cooling plate (522), wherein the electric heater (521) and the miniature cooling plate (522) are not turned on at the same time.

5. A spinning bellows according to claim 1, characterized in that, The inner wall of the cooling duct (3) is equipped with several temperature sensors (12), and each temperature sensor (12) is set to correspond to a polyester fiber.

6. The spinning bellows according to claim 1, characterized in that, The guide plate (2) is installed at an angle, and the cooling air duct (3) forms a downward tapering structure.

7. A spinning bellows according to claim 1, characterized in that, The ventilation slots (21) on the guide plate (2) are horizontal slots, and the ventilation slots (21) are evenly arranged along the height direction of the guide plate (2).

8. A spinning bellows according to claim 1, characterized in that, The coverage area of ​​the ventilation slot (21) is greater than 60% of the cross-sectional area of ​​its corresponding partitioned air cavity (42) in the height direction.

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