A die assist for film processing

Abstract

The application provides a die auxiliary device suitable for film processing, which comprises a dust collection front guard plate arranged on a die lip front side adjusting mechanism and having a structure suitable for the die lip front side adjusting mechanism; the dust collection front guard plate has a front negative pressure air nozzle; a dust collection rear guard plate arranged on a die lip rear side adjusting mechanism and having a structure suitable for the die lip rear side adjusting mechanism; the dust collection rear guard plate has a rear negative pressure air nozzle; a plurality of negative pressure air pipes each having a negative pressure air port, wherein the negative pressure air ports of some of the negative pressure air pipes are communicated with the front negative pressure air nozzle and provide negative pressure air for the front negative pressure air nozzle; the negative pressure air ports of the other negative pressure air pipes are communicated with the rear negative pressure air nozzle and provide negative pressure air for the rear negative pressure air nozzle; and a fan communicated with the plurality of negative pressure air pipes through an air pipe shunt to form negative pressure air in the negative pressure air pipes; wherein the dust collection front guard plate and the dust collection rear guard plate jointly form a negative pressure air cavity cover. The technical scheme of the application can successfully capture and discharge the oligomers just after the oligomers are separated from the die lip.

Description

Technical Field

[0001] This invention belongs to the field of thin film processing equipment and relates to a die head auxiliary device suitable for thin film processing. Background Technology

[0002] In PET film production, the die head serves to evenly spread and extrude the melt in the melt pipeline after passing through the die head, and then rapidly cool and cast it into a sheet by adjacent casting rollers. Specifically, the melt spreads out in the die head cavity after passing through the distribution block, forming a wide sheet of melt that flows out from the die head lip.

[0003] When PET melt flows out of the die lip, a small amount of low-molecular-weight gases are released. These gases are at a relatively high temperature and easily condense and accumulate when they encounter relatively cooler surrounding areas. The condensed oligomers form powdery substances that adhere to multiple locations on the die head. Due to the influence of airflow in the area, these powdery substances can easily fall onto the cast film, causing product contamination.

[0004] To remove low-molecular-weight gases, equipment manufacturers typically install an exhaust device above the die head, as illustrated in Chinese patent CN206999567U, "A suction device for a thin film die head." However, in existing technologies, the die head structure, viewed from the side, is an inverted triangle that is wide and thick at the top and narrow and thin at the bottom. The lip is located below the inverted triangle, and the die head itself blocks the exhaust air from above. At the same time, the die lip is close to the casting roller, creating a narrow space that easily generates dead zones for airflow, which is not conducive to the discharge of oligomer gases. Summary of the Invention

[0005] The purpose of this invention is to provide a die head auxiliary device suitable for thin film processing. By installing a negative pressure air device at the die lip, the oligomer can be easily captured and discharged as soon as it leaves the die lip.

[0006] To achieve the above objectives, the present invention proposes the following technical solution: a die head auxiliary device suitable for thin film processing, the die head comprising a die head body, a die head lip connected to the die head body, a die head lip front adjustment mechanism disposed on the front side of the die head and controlling the position of the front side of the die head lip, and a die head lip rear adjustment mechanism disposed on the rear side of the die head and controlling the position of the rear side of the die head lip; defined, the front side is the direction in which melt flows out of the die head and forms a thin film; the rear side is the opposite direction relative to the front side; comprising:

[0007] A dust collection front guard plate is mounted on the front adjustment mechanism of the mold lip and has a structure adapted to the front adjustment mechanism of the mold lip; the dust collection front guard plate has a front negative pressure nozzle;

[0008] The dust collection rear guard plate is mounted on the adjustment mechanism at the rear of the mold lip and has a structure adapted to the adjustment mechanism at the rear of the mold lip; the dust collection rear guard plate has a rear negative pressure nozzle;

[0009] Multiple negative pressure ducts are equipped with negative pressure air outlets. Some of the negative pressure ducts have negative pressure air outlets connected to the front negative pressure air nozzles and provide negative pressure air to the front negative pressure air nozzles; other negative pressure ducts have negative pressure air outlets connected to the rear negative pressure air nozzles and provide negative pressure air to the rear negative pressure air nozzles.

[0010] The fan is connected to multiple negative pressure ducts through a duct splitter to create negative pressure air in the negative pressure ducts;

[0011] The dust collection front guard plate and the dust collection rear guard plate together form a negative pressure air chamber cover.

[0012] As an improved technical solution of this application, the front negative pressure nozzle has a distance of no more than 6mm relative to the lip of the mold head.

[0013] As an improved technical solution of this application, the rear negative pressure nozzle has a distance of no more than 6mm relative to the lip of the mold head.

[0014] As an improved technical solution of this application, one end of the front negative pressure nozzle of the dust collection front guard plate has a sloping structure extending towards the mold head lip, and the sloping structure is attached to the front side of the mold head lip.

[0015] As an improved technical solution of this application, the front negative pressure nozzle of the dust collection front guard plate is provided with multiple guide plates. The multiple guide plates are designed with different spacing and different angles to make the air pressure even and stable in the lateral direction of the front negative pressure nozzle of the dust collection front guard plate.

[0016] As an improved technical solution of this application, the rear negative pressure nozzle of the dust collection rear guard plate has a sloping structure extending towards the mold head lip, and the sloping structure is attached to the rear side of the mold head lip.

[0017] As an improved technical solution of this application, the rear negative pressure nozzle of the dust collection rear guard plate is provided with multiple guide plates. The multiple guide plates are designed with different spacing and different angles to make the air pressure even and stable in the lateral direction of the rear negative pressure nozzle of the dust collection rear guard plate.

[0018] As an improved technical solution of this application, the front adjustment mechanism of the mold lip has a slot, and the front dust collection guard plate has a buckle. The front dust collection guard plate is installed on the front adjustment mechanism of the mold lip by the cooperation of the buckle and the slot.

[0019] As an improved technical solution of this application, the mold lip rear adjustment mechanism has a slot, and the dust collection rear guard plate has a buckle. The dust collection rear guard plate is installed on the mold lip rear adjustment mechanism by the cooperation of the buckle and the slot.

[0020] As an improved technical solution in this application, the negative pressure air outlets are all designed as conical structures. Definition: A conical structure refers to a structure with a large end and a small end, wherein the large end is close to the lip of the mold head and the small end is close to the fan; the small end of the conical structure is connected to the negative pressure air duct.

[0021] As can be seen from the above technical solutions, the technical solution of the present invention provides...

[0022] 1. The negative pressure nozzle is only 6mm away from the die lip, which is the smallest known design between the negative pressure nozzle and the die lip, ensuring the capture effect of oligomers.

[0023] 2. The negative pressure dust collection hood (the structure formed by the front dust collection plate and the rear dust collection plate) is designed according to the shape of the mold head. It adopts an irregular shape fitting design that matches the shape of both sides of the mold head. It does not occupy the space between the mold head and the casting roller on site, does not change the configuration of other existing equipment, and does not affect the original function of the equipment. At the same time, it makes full use of the original mold head screw hole positions for installation, without the need to re-process the installation holes and without damaging the original mold head structure.

[0024] 3. The negative pressure dust collection hood (the structure formed by the front dust collection guard plate and the rear dust collection guard plate) also serves as a guard plate, protecting the mold head lip and adjusting bolts.

[0025] 4. The dust cover is fixed to the mold head, utilizing the existing screw holes without requiring re-machining of the mounting holes, and does not damage the original mold head structure.

[0026] 5. One end of the front dust collection guard plate has a beveled structure, which is attached to the front side of the die lip; one end of the rear dust collection guard plate also has a beveled structure, which is attached to the rear side of the die lip, resulting in a flat, staggered layer at the lower edge of the negative pressure nozzle. Simultaneously, the beveled edges of both the front and rear dust collection guard plates fit tightly to the lip without any steps, preventing the accumulation of oligomers at the lip position. This also does not interfere with the operator's daily cleaning of the die lip.

[0027] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0028] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0029] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein:

[0030] Figure 1 A schematic diagram of the structure of a die head auxiliary device suitable for thin film processing is shown in this application;

[0031] Figure 2 A schematic diagram of the structure at the lip of the mold head is shown;

[0032] Figure 3 Draw a schematic diagram of the dust collection back panel structure;

[0033] Figure 4 Draw a schematic diagram of the mold head lip structure;

[0034] Figure 5 A schematic diagram of the three-dimensional structure of the dust collection back panel is shown.

[0035] In the diagram, 1. Vortex fan; 2. Dust duct distributor; 3. Negative pressure duct; 4. Dust collection front guard plate; 5. Melt; 6. Casting roller; 7. Dust collection rear guard plate; 8. Die head lip; 9. Die head body; 10. Air volume regulating valve; 11. Negative pressure air outlet; 12. Die lip front adjustment mechanism; 13. Rear negative pressure air nozzle; 14. Connecting plate; 15. Guide plate; 16. Buckle; 17. Negative pressure air outlet A; 18. Heating rod; 19. Sloping structure. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art.

[0037] like Figure 1 As shown, a die head auxiliary device suitable for thin film processing is provided, which uses a negative pressure air device installed at the die lip of the die head to ensure that oligomers are captured and discharged smoothly as soon as they leave the die lip.

[0038] To achieve the above objectives, the present invention proposes the following technical solution: a die head auxiliary device suitable for thin film processing, wherein the die head includes a die head body 9 (a prior art structure, which is not improved in this application and therefore not described in detail), a die head lip 8 connected to the die head body 9 (a prior art structure, which is not improved in this application and therefore not described in detail), a die lip front adjustment mechanism 12 located on the front side of the die head and controlling the front side of the die head lip 8 (a prior art structure, which is not improved in this application and therefore not described in detail), and a die lip rear adjustment mechanism located on the rear side of the die head and controlling the rear side of the die head lip 8 (a prior art structure, which is not improved in this application and therefore not described in detail); defined, the front side is the direction in which the melt 5 flows out of the die head and forms a thin film; the rear side is the opposite direction relative to the front side. This application adds the following structure based on the prior art:

[0039] The dust collection front guard plate 4 is provided on the front adjustment mechanism of the mold lip and has a structure adapted to the front adjustment mechanism 12 of the mold lip; the dust collection front guard plate 4 has a front negative pressure air nozzle; in order to facilitate cleaning, the dust collection front guard plate 4 has a connecting plate 14 at the end of the front negative pressure air nozzle away from the mold head.

[0040] like Figure 3 and Figure 5 The dust collection rear guard plate 7 is located on the adjustment mechanism on the rear side of the mold lip and has a structure adapted to the adjustment mechanism on the rear side of the mold lip; the dust collection rear guard plate 7 has a rear negative pressure nozzle 13; in order to facilitate cleaning, the dust collection rear guard plate 7 has a connecting plate 14 at the end of the rear negative pressure nozzle 13 away from the mold head.

[0041] Definition of negative pressure nozzle: It is a flat opening in the dust collection front / rear guard plate that is the first point of contact between the low molecular weight oligomers and the suction position. It is flush with the mold lip and has a length of 1800mm.

[0042] Multiple negative pressure air ducts 3, of which the negative pressure air outlets 11 of some negative pressure air ducts 3 are connected to the dust collection front guard plate 4 and provide negative pressure air to the front negative pressure air nozzle; the negative pressure air outlets 11 of other negative pressure air ducts 3 are connected to the dust collection rear guard plate 7 and provide negative pressure air to the rear negative pressure air nozzle 13.

[0043] The fan (vortex fan) is connected to multiple negative pressure ducts 3 through the duct splitter 2 so that negative pressure air can be generated in the negative pressure ducts 3;

[0044] The dust collection front guard plate 4 and the dust collection rear guard plate 7 together form a negative pressure air chamber hood. To avoid secondary pollution, the fan adopts a high-speed all-aluminum shell fan, which is resistant to high temperature and high dust environment, ensuring that the oligomers have little residue in the fan blades and are easy to discharge; the discharged oligomer gas is connected to the exhaust gas treatment device at the outdoor exhaust outlet to ensure that the dust does not pollute the environment.

[0045] Its working principle can be described by its working method. A method for removing oligomer gases in PET production includes the following steps:

[0046] Step 1: Provide two sets of negative pressure air vents A17 (formed by the front negative pressure air nozzle and the rear negative pressure air nozzle 13) that fit into the mold lip. These are installed at the front and rear ends of the mold head and mold lip respectively (i.e., the front negative pressure air nozzle is installed at the front end of the mold head and mold lip, and the rear negative pressure air nozzle 13 is installed at the rear end of the mold head and mold lip). This allows low-molecular-weight aggregates to be effectively captured and discharged by the negative pressure air vents A17 when they vaporize as they detach from the mold lip along with the melt 5. The negative pressure air vents A17 are attached to a negative pressure air chamber cover, which is reliably and fixedly installed at both ends of the mold lip.

[0047] Step 2: Connect the dust collection front guard plate 4 and dust collection rear guard plate 7 to the duct splitter 2 using negative pressure duct 3, and connect them to the air inlet of the vortex fan 1 through the air volume regulating valve 10 (the fan is connected to multiple negative pressure ducts 3 through the duct splitter 2 so that negative pressure air can be formed in the negative pressure ducts 3; multiple negative pressure ducts 3, of which the negative pressure air outlets 11 of some negative pressure ducts 3 are connected to the front negative pressure air nozzle and provide negative pressure air to the front negative pressure air nozzle; the negative pressure air outlets 11 of other negative pressure ducts 3 are connected to the rear negative pressure air nozzle 13 and provide negative pressure air to the rear negative pressure air nozzle 13).

[0048] Step 3: When the vortex fan 1 is started, a single vortex fan 1 can generate suction pressure for the exhaust volume. After the air volume is regulated by the negative pressure air duct 3 and the air volume regulating valve 10, and then guided by the guide plate 15 inside the dust collection front guard plate 4 (the guide plate 15 designed in the front negative pressure air nozzle) and the guide plate 15 inside the dust collection rear guard plate 7 (the guide plate 15 designed in the rear negative pressure air nozzle 13), a uniform and stable suction negative pressure can be generated at the air outlet, effectively capturing and expelling the low molecular aggregates that have just left the lip and are in the form of smoke.

[0049] Step 4: When the captured and discharged smoke-like low-molecular-weight aggregates are discharged from the outlet of the vortex fan 1, they turn into fine particulate dust due to the decrease in temperature. After being adsorbed and filtered by the activated carbon adsorption device at the exhaust outlet, the discharged exhaust gas meets environmental protection requirements.

[0050] As an improved technical solution of this application, one end of the front negative pressure nozzle of the dust collection front guard plate 4 extends towards the die lip 8 with a beveled structure 19, which is attached to the front side of the die lip 8. As an improved technical solution of this application, one end of the front negative pressure nozzle of the dust collection rear guard plate 7 extends towards the die lip 8 with a beveled structure 19, which is attached to the rear side of the die lip 8. A staggered structure is formed between the dust collection front guard plate 4, the die lip 8, and the dust collection rear guard plate 7; compared with the thickness of approximately 15 cm of existing finished negative pressure nozzles on the market, this staggered design of this application both brings it infinitely closer to the die lip and increases the distance from the precision casting roller 6 directly below. Ultimately, it ensures that the front negative pressure nozzle has a distance of no more than 6 mm relative to the die lip; the rear negative pressure nozzle 13 has a distance of no more than 6 mm relative to the die lip. Meanwhile, since the inclined structure 19 is in close contact with the die lip 8, the heating rod 18 of the die lip 8 (the structure of the die lip 8 with the heating rod 18 is a prior art structure) can be used to heat and transfer heat to the entire nozzle and the dust collection front guard plate 4, so that the temperature of the entire hood can be controlled at 200℃, ensuring that the oligomers do not accumulate in the hood due to the temperature drop, and ensuring the discharge effect of the oligomer airflow.

[0051] Existing negative pressure nozzles cannot achieve this function. Currently, the distance between the die lip and the precision casting roller 6 directly below it in the production workstation is 30mm. Existing finished negative pressure nozzles on the market are about 15cm thick and weigh about 60kg, which is relatively thick and heavy, making it impossible to achieve a close fit to the die lip 8 during installation. At the same time, if the nozzle is too thick and the installation distance is controlled too closely, there is a risk of it hitting the roller, causing scratches on the surface of the precision components. For safety reasons, this application redesigns this staggered design, which is both infinitely close to the die lip and increases the distance from the precision casting roller 6 directly below. In addition, this application adopts a sloping structure design to fit tightly with the die lip, without steps, ensuring that the die lip position does not accumulate oligomers due to steps. At the same time, it does not affect the operator's daily cleaning of the mold lip (because when the machine is stopped, the operator needs to use a bamboo knife to scrape the material inside the mold lip 8. If the negative pressure nozzle is not too close to the mold lip or parallel to the mold lip, it will affect the operation of the bamboo knife. At the same time, the scraped residue will stick to the nozzle and is not easy to clean. After the machine is turned on, it will scrape the normal melt 5 and affect the product quality).

[0052] As an improved technical solution in this application, such as Figure 2 and Figure 4The oligomer airflow escaping from the die lip 8 is uneven along its length due to the influence of the external airflow. The negative pressure on both sides of the die lip 8 is slightly greater than that in the middle. The front negative pressure nozzle is equipped with guide plates 15 to ensure the air pressure is balanced and stable laterally. Specifically, multiple guide plates 15 are designed with different spacings and angles according to fluid mechanics to ensure the air pressure is balanced and stable laterally at the front negative pressure nozzle of the dust collection front guard plate 4. The rear negative pressure nozzle 13 of the dust collection rear guard plate 7 is also equipped with multiple guide plates 15. Based on fluid mechanics principles, these guide plates are designed with different spacings and angles to ensure the air pressure is balanced and stable laterally at the rear negative pressure nozzle 13 of the dust collection rear guard plate 7. This allows the oligomers escaping from the die lip 8 to be sucked away in the shortest possible time, ensuring the capture capacity of oligomers along the length of the die outlet; simultaneously, it ensures uniform suction air pressure across the entire width.

[0053] The negative pressure vent 11 is designed with a conical structure. A conical structure is defined as a triangular structure with a large end and a small end, where the large end is near the die lip 8 and the small end is near the fan. The air pressure at the narrowest point of the conical nozzle is sufficient to draw away the oligomer gas while preventing excessive negative pressure that could disturb the melt 5. Multiple exhaust ducts are designed horizontally at the top of the conical structure, connected to the exhaust fan to ensure uniform and optimal exhaust performance.

[0054] For ease of installation, the front adjustment mechanism of the mold lip has a slot, and the front dust collection guard plate 4 has a buckle 16. The front dust collection guard plate 4 is installed on the front adjustment mechanism of the mold lip through the engagement of the buckle 16 and the slot. The rear adjustment mechanism of the mold lip has a slot, and the rear dust collection guard plate 7 has a buckle 16. The rear dust collection guard plate 7 is installed on the rear adjustment mechanism of the mold lip through the engagement of the buckle 16 and the slot.

[0055] In the actual production process, there was no dust collection device at this location on the die head, causing oligomers in the melt to accumulate and form powdery substances, which seriously affected product quality. After the implementation of this device, the number of oligomer dots on the film surface has been reduced from about 80 per 100 meters to less than 6 per 100 meters through online detection equipment.

[0056] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A die head auxiliary device suitable for thin film processing, the die head comprising a die head body, a die head lip connected to the die head body, a die head front adjustment mechanism disposed on the front side of the die head and controlling the position of the front side of the die head lip, and a die head rear adjustment mechanism disposed on the rear side of the die head and controlling the position of the rear side of the die head lip. By definition, the front side is the direction in which the melt flows out from the die head and forms a thin film; The rear side is the opposite direction to the front side; characterized in that it includes: A dust collection front guard plate is mounted on the front adjustment mechanism of the mold lip and has a structure adapted to the front adjustment mechanism of the mold lip; the dust collection front guard plate has a front negative pressure nozzle; The dust collection rear guard plate is mounted on the adjustment mechanism at the rear of the mold lip and has a structure adapted to the adjustment mechanism at the rear of the mold lip; the dust collection rear guard plate has a rear negative pressure nozzle; Multiple negative pressure ducts are equipped with negative pressure air outlets. Some of the negative pressure ducts have negative pressure air outlets connected to the front negative pressure air nozzles and provide negative pressure air to the front negative pressure air nozzles; other negative pressure ducts have negative pressure air outlets connected to the rear negative pressure air nozzles and provide negative pressure air to the rear negative pressure air nozzles. The fan is connected to multiple negative pressure ducts through a duct splitter to create negative pressure air in the negative pressure ducts; Among them, the dust collection front guard plate and the dust collection rear guard plate together form a negative pressure air chamber cover; The front negative pressure nozzle of the dust collection front guard plate has a sloping structure extending towards the mold head lip. This sloping structure is attached to the front side of the mold head lip. The front negative pressure nozzle of the dust collection front guard plate is equipped with multiple guide plates. The multiple guide plates are designed with different spacing and different angles to make the air pressure in the lateral direction of the front negative pressure nozzle of the dust collection front guard plate balanced and stable. The rear negative pressure nozzle of the dust collection rear guard plate has a beveled structure extending towards the mold head lip. This beveled structure is attached to the rear side of the mold head lip. The rear negative pressure nozzle of the dust collection rear guard plate is equipped with multiple guide plates. The multiple guide plates are designed with different spacing and different angles to make the air pressure in the lateral direction of the rear negative pressure nozzle of the dust collection rear guard plate balanced and stable. The front negative pressure nozzle has a distance of no more than 6 mm relative to the mold head lip; the rear negative pressure nozzle has a distance of no more than 6 mm relative to the mold head lip.

2. The die head auxiliary device for thin film processing according to claim 1, characterized in that, The mold lip front adjustment mechanism has a slot, and the dust collection front guard plate has a buckle. The dust collection front guard plate is installed on the mold lip front adjustment mechanism by the cooperation of the buckle and the slot.

3. The die head auxiliary device for thin film processing according to claim 1, characterized in that, The mold lip rear adjustment mechanism has a slot, and the dust collection rear guard plate has a buckle. The dust collection rear guard plate is installed on the mold lip rear adjustment mechanism by the cooperation of the buckle and the slot.

4. The die head auxiliary device for thin film processing according to claim 1, characterized in that, All negative pressure air outlets are designed with a conical structure. Definition: A conical structure is a structure with a large end and a small end, where the large end is close to the lip of the mold head and the small end is close to the fan; the small end of the conical structure is connected to the negative pressure air duct.

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