Rotary traction blown film production equipment and rotary traction blown film production process

Abstract

A rotary traction blown film production device includes an extrusion die head, above which are arranged a first horizontal movable guide roller, a second horizontal movable guide roller, a third horizontal movable guide roller, and a fourth horizontal movable guide roller; it also includes photoelectric sensors for detecting the left and right edge positions of a double-layer plastic film; the air holes on the surface of the fourth horizontal movable guide roller are divided into left and right halves, with the air outlet direction of the air holes in the left half inclined to the left and the air outlet direction of the air holes in the right half inclined to the right; the roller cavity of the fourth horizontal movable guide roller is divided into two small chambers, left and right, with the air inlet of the left small chamber connected to a left branch air inlet hose, and the air inlet of the right small chamber connected to a right branch air inlet hose; a blower is connected to the left branch air inlet hose and the right branch air inlet hose through a main air supply pipe and an electromagnetic proportional valve. This invention can automatically correct lateral position deviations of the film, and the correction process does not damage the film, resulting in good winding quality.

Description

Technical Field

[0001] This invention belongs to the field of plastic film production technology, specifically relating to a rotary traction blown film production equipment and a rotary traction blown film production process. Background Technology

[0002] During the production of blown film, the plastic raw material is melted and extruded through the annular extrusion nozzle of the die head to become a cylindrical film bubble. Then, the traction clamping roller flattens the film bubble into a double-layer film. The double-layer film passes around the horizontal fixed guide roller and is finally wound up by the winding shaft. The installation direction of the horizontal fixed guide roller is parallel to the central axis of the winding shaft.

[0003] However, due to mechanical design, structure, and processing, the thickness of the cylindrical film bubble extruded from the annular extrusion nozzle of the blown film equipment varies at different points. For example, the thickness of the film bubble at the corresponding position of the injection nozzle will be significantly thicker. Moreover, this thickness deviation is a systematic error. That is, if a point in a certain position of the film bubble is thicker, the subsequent film bubbles will continue to be thicker in that position. Conversely, if a point in a certain position of the film bubble is thinner, the subsequent film bubbles will continue to be thinner in that position. Therefore, if the film is wound in the traditional way, without any treatment, the thick spots (or bumps) will gradually accumulate and stack at the same position on the roll, resulting in a serious uneven thickness of the wound film and poor winding quality, which is known in the industry as "bursting".

[0004] To overcome the above-mentioned shortcomings, a rotary traction device has been designed, such as the structure shown in Chinese Utility Model Patent CN203331410U. It can make the traction clamping roller rotate back around the central axis of the annular extrusion nozzle (the central axis of the annular extrusion nozzle theoretically overlaps with the central axis of the film bubble). In this way, the distribution of the film thickness points on the roll material presents a wave-like distribution state, which is dispersed along the axial direction of the roll material. This effectively solves the problem of winding accumulation caused by systematic thickness errors, and makes the film thickness points evenly distributed along the axial direction of the roll material, so that they do not accumulate in the same position, thus achieving the purpose of smooth winding.

[0005] In the aforementioned rotary traction structure, to ensure the film on the continuously rotating traction roller is stably transferred to the stationary horizontal guide roller, a first horizontal movable guide roller 1, a second horizontal movable guide roller 2, a third horizontal movable guide roller 3, and a fourth horizontal movable guide roller 4 are typically installed between the traction roller 30 and the horizontal fixed guide roller 5. Viewed vertically, the vertical distance between the fourth horizontal movable guide roller 4, the third horizontal movable guide roller 3, the second horizontal movable guide roller 2, and the first horizontal movable guide roller 1 and the traction roller 30 increases sequentially. Specifically, the horizontal positions of the first horizontal movable guide roller 1 and the third horizontal movable guide roller 3 are far from the central axis s of the annular extrusion port, while the horizontal positions of the second horizontal movable guide roller 2 and the fourth horizontal movable guide roller 4 are close to the central axis of the annular extrusion port.Figure 1 As shown; the two ends of the first horizontal movable guide roller 1 are mounted on the first guide roller bracket 11, the two ends of the second horizontal movable guide roller 2 are mounted on the second guide roller bracket 12, the two ends of the third horizontal movable guide roller 3 are mounted on the third guide roller bracket 13, and the two ends of the fourth horizontal movable guide roller 4 are mounted on the fourth guide roller bracket 14. Through the gear transmission mechanism 60, the traction clamping roller 30, the first guide roller bracket 11, the second guide roller bracket 12, the third guide roller bracket 13, and the fourth guide roller bracket 14 are driven to rotate back and forth at a uniform speed around the central axis s of the annular extrusion port. The first guide roller bracket, the second guide roller bracket, the third guide roller bracket, and the fourth guide roller bracket correspondingly drive the first horizontal movable guide roller... Roller 1, second horizontal movable guide roller 2, third horizontal movable guide roller 3, and fourth horizontal movable guide roller 4 rotate back and forth at a constant speed around the central axis of the annular extrusion port. The traction clamping roller 30 and the first horizontal movable guide roller 1 rotate synchronously, and the rotation angles of the first horizontal movable guide roller 1, second horizontal movable guide roller 2, third horizontal movable guide roller 3, and fourth horizontal movable guide roller 4 are 4:3:2:1. When the first horizontal movable guide roller 1 is parallel to the horizontal fixed guide roller 5, the second horizontal movable guide roller 2, third horizontal movable guide roller 3, and fourth horizontal movable guide roller 4 are also parallel to the horizontal fixed guide roller. At this time, the direction of the central axis of the fourth horizontal movable guide roller 4 is called the reference direction.

[0006] During operation, the plastic film passes through the traction clamping roller 30 and then sequentially passes through the first horizontal movable guide roller 1, the second horizontal movable guide roller 2, the third horizontal movable guide roller 3, and the fourth horizontal movable guide roller 4 before reaching the horizontal fixed guide roller 5. Regardless of the angle at which the traction clamping roller rotates, due to the folding action of the first, second, third, and fourth horizontal movable guide rollers, the plastic film theoretically travels in a direction perpendicular to the horizontal fixed guide roller when it reaches it, thus smoothly achieving winding. For example, in... Figure 2 In the process, the film bubble 80 is flattened into a double-layer plastic film 8 by the traction clamping roller 30. When each horizontal movable guide roller rotates 0°, the double-layer plastic film 8 reaches the horizontal fixed guide roller 5, and its running direction is perpendicular to the horizontal fixed guide roller 5; for example, in Figure 3 In the process, when the first horizontal movable guide roller 1 rotates 180°, the plastic film, after passing the traction clamping roller 30, first passes around the first horizontal movable guide roller 1, becoming... Figure 3 The plastic film fragments abcd in (in) Figure 3 (Moving to the right in the diagram), then bypassing the second horizontal movable guide roller 2, becoming... Figure 3 The plastic film cdfe shown in the fragment (in) Figure 3 (It moves upwards in the diagram), then bypasses the third horizontal movable guide roller 3, becoming... Figure 3 The fragment shown in efhg (in Figure 3 (Running downwards in the diagram), then bypassing the fourth horizontal movable guide roller 4, becoming... Figure 3The fragment shown in ghmn (in) Figure 3 (Move to the right in the image). From Figure 3 It can be seen that when the ghmn fragments of the plastic film reach the horizontal fixed guide roller 5, their running direction is also perpendicular to the horizontal fixed guide roller 5.

[0007] However, as the horizontal movable guide rollers twist back and forth around the central axis of the annular extrusion port, the film surface and the surface of the horizontal movable guide rollers will be relatively twisted and rubbed. At this time, the film has just been extruded and its physical properties have not yet stabilized. Therefore, the film is prone to irregular tearing or scratching during the twisting process of rotation and traction.

[0008] To mitigate the severity of the aforementioned tears or scratches, the second, third, and fourth horizontal movable guide rollers are designed as air cushion rollers. Each air cushion roller has small air holes on its surface and is equipped with a fan that supplies air to the air cushion rollers. As each horizontal movable guide roller twists back and forth around the annular extrusion port, the fan continuously supplies air to the air cushion rollers, forming an air cushion layer on the surface of the second, third, and fourth horizontal movable guide rollers. This effectively avoids the problem of tears or scratches.

[0009] However, during the aforementioned rotary traction process, the lateral position of the left and right edges of the film (i.e., the axial position along the guide rollers) is prone to significant deviation. This is mainly due to the following two reasons: First, during the rotary traction process, the horizontal movable guide rollers at various angles continuously twist, causing the film tension to generate a component force along the axial direction of the horizontal guide rollers to varying degrees. Second, due to the presence of the air cushion layer, the film continuously detaches from the surfaces of the second, third, and fourth horizontal movable guide rollers. The combination of these two factors makes the film prone to irregular displacement along the axial direction of the second, third, and fourth horizontal movable guide rollers, resulting in deviations in the lateral position of the left and right edges of the film (i.e., the axial position along the guide rollers), which in turn causes the left and right edges of the wound film to be uneven (commonly known in the industry as "wagging edges").

[0010] To address the aforementioned issues, an automatic detection mechanism for the lateral position of the film edge and an automatic correction mechanism were designed. The detection mechanism includes photoelectric sensors along the film's running path to detect the position of its left and right edges. These sensors are located downstream of the horizontally fixed guide roller. The automatic correction mechanism comprises a movable adjustment frame mounted on a support, on which several correction guide rollers are installed that directly contact the film. The support also houses a motor that drives the movable adjustment frame to swing. When the detection mechanism detects that the film's offset exceeds a set range, it sends a signal, and the motor of the automatic correction mechanism drives the movable adjustment frame to swing, tilting the correction guide rollers and guiding the film to shift laterally to one side. Because the air cushion rollers swing continuously, and the aforementioned adjustment mechanism (including the support, movable adjustment frame, correction guide rollers, motor, etc.) cannot swing synchronously with the air cushion rollers around the central axis of the annular extrusion port, the aforementioned adjustment mechanism (including the support, movable adjustment frame, correction guide rollers, motor, etc.) is generally installed downstream of the rotary traction mechanism (i.e., downstream of the horizontally fixed guide roller). However, during the process of adjusting the lateral position of the film, the film surface will still rub against the guiding roller. This means that the film surface is easily scratched due to friction. When the lateral width of the film is large or the film viscosity is high, the film will also be torn during the lateral dragging adjustment due to the large frictional resistance. In addition, the existing correction method is limited by the rotation angle of the movable adjustment frame, which limits the correction range (in other words, if the rotation angle of the movable adjustment frame is designed to be too large, it is easier to scratch or tear the film).

[0011] On the other hand, during the aforementioned traction process, due to the presence of the air cushion layer, the film continuously detaches from the surfaces of the second, third, and fourth horizontal movable guide rollers, lacking the force to apply tension to the film in the transverse direction. This results in the film being somewhat loose in the transverse direction and failing to flatten during the rotational traction process (tension along the axis of the guide rollers is called "flattening"). Once the relatively loose film reaches the horizontal fixed guide roller and adheres (slightly sticks) to it, the problem of the film being somewhat loose in the transverse direction becomes difficult to eliminate. This also affects the winding quality, resulting in a film roll that is not dense when finally wound. Summary of the Invention

[0012] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a rotary traction blown film production equipment and a rotary traction blown film production process, which can automatically correct the lateral position deviation of the film, and the correction process will not damage the film, resulting in good winding quality.

[0013] The objective can be achieved as follows: A rotary traction blown film production equipment includes a central controller and an extrusion die. The extrusion die has an annular extrusion port. Above the extrusion die, two traction clamping rollers, a first horizontal movable guide roller, a second horizontal movable guide roller, a third horizontal movable guide roller, and a fourth horizontal movable guide roller are arranged in sequence. The horizontal positions of the first and third horizontal movable guide rollers are far from the central axis of the annular extrusion port, while the horizontal positions of the second and fourth horizontal movable guide rollers are close to the central axis of the annular extrusion port. Downstream of the fourth horizontal movable guide roller, a horizontal fixed guide roller is also provided. Downstream of the horizontal fixed guide roller, a take-up shaft is also provided. The installation direction of the horizontal fixed guide roller is parallel to the take-up shaft.

[0014] The vertical distances between the traction clamping roller, the first horizontal movable guide roller, the second horizontal movable guide roller, the third horizontal movable guide roller, the fourth horizontal movable guide roller, and the annular extrusion port increase sequentially. The traction clamping roller and the first horizontal movable guide roller are mounted on the first support, the second horizontal movable guide roller is mounted on the second support, the third horizontal movable guide roller is mounted on the third support, and the fourth horizontal movable guide roller is mounted on the fourth support. The first support, the second support, the third support, and the fourth support can all rotate horizontally around the central axis of the annular extrusion port. A bidirectional motor is also provided to drive the first support to rotate horizontally around the central axis of the annular extrusion port. A reduction transmission mechanism is provided between the first support and the second support, the third support, and the fourth support. The rotation angle ratio of the first support, the second support, the third support, and the fourth support is maintained at 4:3:2:1. The second horizontal movable guide roller, the third horizontal movable guide roller, and the fourth horizontal movable guide roller are air cushion rollers. Each air cushion roller has a hollow roller cavity, air holes on the surface of each air cushion roller, an air inlet on the end face of the air cushion roller, and a fan to supply air to the air cushion roller.

[0015] It is also equipped with photoelectric sensors for detecting the position of the left and right edges of the double-layer plastic film. The photoelectric sensors are located downstream of the horizontal fixed guide roller and upstream of the take-up shaft. It is also equipped with a central controller, and the photoelectric sensors are connected to the central controller.

[0016] The feature is that: the air holes on the surface of the fourth horizontal movable guide roller are divided into left and right halves, wherein the air outlet direction of the air holes in the left half is inclined to the left, and the air outlet direction of the air holes in the right half is inclined to the right; the roller cavity of the fourth horizontal movable guide roller is divided into two mutually isolated small chambers by a middle partition plate, the air inlet of the left small chamber is located on the left end face of the fourth horizontal movable guide roller, and the air inlet of the right small chamber is located on the right end face of the fourth horizontal movable guide roller; the air inlet of the left small chamber is connected to a left branch air inlet hose, and the air inlet of the right small chamber is connected to a right branch air inlet hose; the fan is connected to the left branch air inlet hose and the right branch air inlet hose through a main air supply pipe and an electromagnetic proportional valve.

[0017] Preferably, the air outlet direction (i.e., the orientation of the air holes) on the surface of the fourth horizontal movable guide roller forms an angle of 45° to 65° with the central axis of the fourth horizontal movable guide roller.

[0018] The term "downstream" refers to the direction in which the thin film moves from upstream to downstream.

[0019] A rotary traction blown film production process, using the aforementioned rotary traction blown film production equipment, includes the following steps: The annular extrusion nozzle of the extrusion die continuously extrudes annular film bubbles. The film bubbles travel between two traction clamping rollers, where they are flattened and folded into a double-layer plastic film. The double-layer plastic film then sequentially passes around a first horizontal movable guide roller, a second horizontal movable guide roller, a third horizontal movable guide roller, and a fourth horizontal movable guide roller, reaching a horizontal fixed guide roller. When the double-layer plastic film reaches the horizontal fixed guide roller, its direction of travel is perpendicular to the horizontal fixed guide roller. After reaching the horizontal fixed guide roller, the double-layer plastic film continues to travel and is finally wound up by a take-up shaft.

[0020] During this process, the bidirectional motor drives the first, second, third, and fourth supports to rotate periodically back and forth around the central axis of the annular extrusion port. The traction clamping roller, the first horizontal movable guide roller, and the first support rotate periodically back and forth synchronously. The second horizontal movable guide roller, the third horizontal movable guide roller, and the fourth horizontal movable guide roller rotate periodically back and forth synchronously. The rotation angle between the first horizontal movable guide roller and the traction clamping roller is maintained at 1:1, while the rotation angles of the first, second, third, and fourth horizontal movable guide rollers are maintained at 4:3:2:1. When the first horizontal movable guide roller is parallel to the horizontal fixed guide roller, the second, third, and fourth horizontal movable guide rollers are also parallel to the horizontal fixed guide roller.

[0021] During this process, the blower continuously blows air into the roller cavities of the second and third horizontal movable guide rollers, and then the air is ejected from the air holes on the surfaces of the second and third horizontal movable guide rollers. The blower also supplies air to the main air supply pipe of the fourth horizontal movable guide roller. This air is distributed into the left branch air inlet hose and the right branch air inlet hose through the electromagnetic proportional valve. The air flowing into the left branch air inlet hose enters the left small chamber of the fourth horizontal movable guide roller through the air inlet on the left side of the fourth horizontal movable guide roller, and is finally ejected from the air holes on the left half of the fourth horizontal movable guide roller. The air flowing into the right branch air inlet hose enters the right small chamber of the fourth horizontal movable guide roller through the air inlet on the right side of the fourth horizontal movable guide roller, and is finally ejected from the air holes on the right half of the fourth horizontal movable guide roller.

[0022] During this process, the photoelectric sensor continuously detects the lateral position of the left and right edges of the double-layer plastic film and transmits the signal to the central controller. When the central controller determines that the lateral position of the double-layer plastic film has shifted to the left, the central controller uses the electromagnetic proportional valve to allocate more air to the right branch intake hose than to the left branch intake hose. When the central controller determines that the lateral position of the double-layer plastic film has shifted to the right, the central controller uses the electromagnetic proportional valve to allocate less air to the right branch intake hose than to the left branch intake hose. When the central controller determines that the lateral position of the double-layer plastic film has not shifted, the central controller uses the electromagnetic proportional valve to allocate the same amount of air to the right branch intake hose as to the left branch intake hose.

[0023] The term "downstream" refers to the direction in which the thin film moves from upstream to downstream.

[0024] The present invention has the following advantages and effects:

[0025] 1. When the lateral position of the film shifts to the left (deviation), the amount of air entering the right branch air inlet hose is greater than that entering the left branch air inlet hose. Therefore, the amount (velocity) of air ejected from the right half of the air holes on the fourth horizontal movable guide roller is greater than that from the left half. The rightward blowing force of the air on the film is greater than the leftward blowing force, causing the film to move to the right and thus correct its lateral position. Conversely, when the lateral position of the film shifts to the right (deviation), the amount of air entering the left branch air inlet hose is greater than that entering the right branch air inlet hose. Therefore, the air ejected from the left half of the air holes on the fourth horizontal movable guide roller... The air volume (velocity) ejected from the first hole is greater than that ejected from the second hole. The leftward blowing force of the air on the film is greater than the rightward blowing force, so the film moves to the left and its lateral position is corrected. When the lateral position of the film does not shift (does not deviate), the air volume entering the left branch air inlet hose is equal to the air volume entering the right branch air inlet hose. Therefore, the air volume (velocity) ejected from the left half of the air inlet of the fourth horizontal movable guide roller is equal to the air volume (velocity) ejected from the right half of the air inlet. The leftward blowing force of the air on the film is equal to the rightward blowing force, so the lateral position of the film remains stable.

[0026] In summary, through the above-mentioned repair and adjustment methods, the present invention can automatically maintain the stability of the film edge position, improve the winding quality, and solve the problem of "edge swaying" of the roll material.

[0027] Second, during the process of adjusting and repairing the film along the lateral position, since the film is suspended on the fourth horizontal movable guide roller, the resistance is small, and it will not cause tearing or scratching of the film.

[0028] Third, because the air ejected from the air holes in the left half exerts a force to the left half of the film, and the air ejected from the air holes in the right half exerts a force to the right half of the film, it is equivalent to applying a force to stretch the film in the transverse direction. In other words, it can stretch and flatten the film in the transverse direction, which is beneficial to improving the density and quality of winding.

[0029] Fourth, the magnitude of the repair range for adjusting and repairing the lateral positional deviation of the film is not limited by the present invention, that is, there is no upper limit. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the common structure of the traditional structure and the rotary traction blown film production equipment of the present invention.

[0031] Figure 2 yes Figure 1 The diagram shows the usage state of the structure when the fourth horizontal movable guide roller rotates at an angle of 0° around the central axis of the annular extrusion nozzle.

[0032] Figure 3 yes Figure 1 The diagram shows the usage state of the structure when the fourth horizontal movable guide roller rotates at an angle of 45° around the central axis of the annular extrusion nozzle.

[0033] Figure 4 This is a schematic diagram of the air path structure of the fourth horizontal movable guide roller in an embodiment of the present invention.

[0034] Figure 5 yes Figure 4 A magnified view of part A in the diagram. Detailed Implementation

[0035] Example 1

[0036] This embodiment also includes a rotary traction blown film production device, as follows: Figure 1 , Figure 2 , Figure 3As shown, the device includes a central controller and an extrusion die 9. The extrusion die 9 has an annular extrusion port 91. Above the extrusion die 9, there are sequentially arranged a traction clamping roller 30, a first horizontal movable guide roller 1, a second horizontal movable guide roller 2, a third horizontal movable guide roller 3, and a fourth horizontal movable guide roller 4. The first horizontal movable guide roller 1 and the third horizontal movable guide roller 3 are positioned horizontally away from the vertical central axis S of the annular extrusion port 91, while the second horizontal movable guide roller 2 and the fourth horizontal movable guide roller 4 are positioned horizontally close to the central axis S of the annular extrusion port 91. Downstream of the fourth horizontal movable guide roller 4, there is a horizontal fixed guide roller 5. Downstream of the horizontal fixed guide roller 5, there is a winding shaft 6. The installation direction of the horizontal fixed guide roller 5 is parallel to the winding shaft 6. The vertical distance between the moving guide roller 4 and the annular extrusion port 91 increases sequentially; the traction clamping roller 30 and the first horizontal movable guide roller 1 are mounted on the first bracket 11, the second horizontal movable guide roller 2 is mounted on the second bracket 12, the third horizontal movable guide roller 3 is mounted on the third bracket 13, and the fourth horizontal movable guide roller 4 is mounted on the fourth bracket 14; the first bracket 11, the second bracket 12, the third bracket 13, and the fourth bracket 14 can all rotate horizontally around the central axis S of the annular extrusion port 91; a bidirectional motor is also provided to drive the first bracket 11 to rotate horizontally around the central axis of the annular extrusion port, and a reduction transmission mechanism 60 is provided between the first bracket 11 and the second bracket 12, the third bracket 13, and the fourth bracket 14, and the rotation angle ratio of the first bracket 11, the second bracket 12, the third bracket 13, and the fourth bracket 14 is maintained at 4:3:2:1, as shown. Figure 1 As shown; the second horizontal movable guide roller 2, the third horizontal movable guide roller 3, and the fourth horizontal movable guide roller 4 are air cushion rollers. Each air cushion roller has a hollow roller cavity, each air cushion roller surface has air holes, the end face of the air cushion roller has an air inlet, and a fan is also provided to supply air to the air cushion roller. Figure 2 , Figure 3 As shown, a photoelectric sensor 7 is also provided for detecting the position of the left and right edges of the double-layer plastic film. The photoelectric sensor 7 is located downstream of the horizontal fixed guide roller 5 and upstream of the winding shaft 6. A central controller is also provided, and the photoelectric sensor is connected to the central controller.

[0037] The features of Embodiment 1 of the present invention are as follows: Figure 4 , Figure 5 As shown: The air holes on the surface of the fourth horizontal movable guide roller 4 are divided into left and right halves. The air outlet direction of the air hole 41 located in the left half is inclined to the left. The air outlet direction of the air hole 41 located in the left half (i.e., the direction of the air hole, such as...) Figure 5 (in the CB direction) and the center axis of the fourth horizontal movable guide roller 4 (e.g.) Figure 4The MN line forms a 45° angle; the air outlet direction of the vent 42 located in the right half is tilted to the right, and the air outlet direction of the vent 42 located in the right half (i.e., the direction of the vent, such as...) Figure 5 (in the FE direction) and the central axis of the fourth horizontal movable guide roller 4 (e.g.) Figure 4 The middle MN line also forms an angle of 45°. Figure 4 , Figure 5 As shown, the interior of the fourth horizontal movable guide roller is divided into two isolated small chambers, namely the left small chamber 43 and the right small chamber 44, by a middle partition 40. The air inlet 45 of the left small chamber 43 is located on the left end face of the fourth horizontal movable guide roller 4, and the air inlet 46 of the right small chamber 44 is located on the right end face of the fourth horizontal movable guide roller 4. The air inlet 45 of the left small chamber 43 is connected to the left branch air inlet hose 47, and the air inlet 46 of the right small chamber 44 is connected to the right branch air inlet hose 48. The fan 72 is connected to the left branch air inlet hose 47 and the right branch air inlet hose 48 through a main air supply pipe 49 and an electromagnetic proportional valve 71.

[0038] Example 2

[0039] A rotary traction blown film production process, using the rotary traction blown film production equipment of Example 1, includes the following steps: the annular extrusion port 91 of the extrusion die 9 continuously extrudes annular film bubbles 80. The film bubbles 80 run between two traction clamping rollers 30, and the annular film bubbles 80 are flattened and folded by the two traction clamping rollers 30 to form a double-layer plastic film 8. Then, the double-layer plastic film 8 sequentially passes around the first horizontal movable guide roller 1, the second horizontal movable guide roller 2, the third horizontal movable guide roller 3, and the fourth horizontal movable guide roller 4, and reaches the horizontal fixed guide roller 5. When the double-layer plastic film 8 reaches the horizontal fixed guide roller 5, its running direction is perpendicular to the horizontal fixed guide roller 5. After the double-layer plastic film 8 reaches the horizontal fixed guide roller 5, it continues to run and is finally wound up by the take-up shaft 6.

[0040] In the above process, the bidirectional motor drives the first support 12, the second support 12, the third support 13, and the fourth support 14 to rotate periodically back and forth around the central axis S of the annular extrusion port. The traction clamping roller 30, the first horizontal movable guide roller 1, and the first support 11 rotate synchronously back and forth periodically; the second horizontal movable guide roller 2 and the second support 12 rotate synchronously back and forth periodically; the third horizontal movable guide roller 3 and the third support 13 rotate synchronously back and forth periodically; and the fourth horizontal movable guide roller 4 and the fourth support 14 rotate synchronously back and forth periodically. The rotation angle between the first horizontal movable guide roller 1 and the traction clamping roller 30 is maintained at 1:1, while the rotation angles of the first horizontal movable guide roller 11, the second horizontal movable guide roller 12, the third horizontal movable guide roller 13, and the fourth horizontal movable guide roller 14 are maintained at 4:3:2:1. When the first horizontal movable guide roller 1 is parallel to the horizontal fixed guide roller 5, the second horizontal movable guide roller 2, the third horizontal movable guide roller 3, and the fourth horizontal movable guide roller 4 are also parallel to the horizontal fixed guide roller 5. Figure 2 As shown;

[0041] During the above process, the blower continuously blows air into the roller cavities of the second horizontal movable guide roller 2 and the third horizontal movable guide roller 3, and then the air is ejected from the air holes on the surface of the second horizontal movable guide roller and the third horizontal movable guide roller; the blower 72 also supplies air to the main air supply pipe 49 of the fourth horizontal movable guide roller 4. The air in the main air supply pipe 49 is distributed by the electromagnetic proportional valve 71 into the left branch air inlet hose 47 and the right branch air inlet hose 48. The air flowing into the left branch air inlet hose 47 enters the left small chamber 43 of the fourth horizontal movable guide roller 4 through the air inlet 45 on the left side of the fourth horizontal movable guide roller 4, and is finally ejected from the air hole 41 on the left half of the fourth horizontal movable guide roller; while the air flowing into the right branch air inlet hose 48 enters the right small chamber 44 of the fourth horizontal movable guide roller 4 through the air inlet 46 on the right side of the fourth horizontal movable guide roller 4, and is finally ejected from the air hole 42 on the right half of the fourth horizontal movable guide roller.

[0042] During the above process, the photoelectric sensor 7 continuously detects the lateral position of the left and right edges of the double-layer plastic film 8 and transmits the signal to the central controller. When the central controller determines that the lateral position of the double-layer plastic film 8 has shifted to the left, the central controller uses the electromagnetic proportional valve 71 to make the amount of air allocated to the right branch intake hose 48 more than the amount of air allocated to the left branch intake hose 47, so the double-layer plastic film 8 moves to the right to correct the deviation. When the central controller determines that the lateral position of the double-layer plastic film 8 has shifted to the right, the central controller uses the electromagnetic proportional valve 71 to make the amount of air allocated to the right branch intake hose 48 less than the amount of air allocated to the left branch intake hose 47, so the double-layer plastic film 8 moves to the left to correct the deviation. When the central controller determines that the lateral position of the double-layer plastic film 8 has not shifted, the central controller uses the electromagnetic proportional valve 71 to make the amount of air allocated to the right branch intake hose 48 equal to the amount of air allocated to the left branch intake hose 47.

[0043] In the above embodiment one, the angle between the air outlet direction (i.e., the direction of the air holes) on the surface of the fourth horizontal movable guide roller and the central axis of the fourth horizontal movable guide roller can be changed to 40° or 65°.

Claims

1. A rotary traction blown film production device, comprising a central controller and an extrusion die, the extrusion die having an annular extrusion orifice, and two traction clamping rollers, a first horizontal movable guide roller, a second horizontal movable guide roller, a third horizontal movable guide roller, and a fourth horizontal movable guide roller arranged sequentially above the extrusion die, wherein the horizontal positions of the first and third horizontal movable guide rollers are far from the central axis of the annular extrusion orifice, while the horizontal positions of the second and fourth horizontal movable guide rollers are close to the central axis of the annular extrusion orifice, a horizontal fixed guide roller is arranged downstream of the fourth horizontal movable guide roller, and a take-up shaft is arranged downstream of the horizontal fixed guide roller, the installation direction of the horizontal fixed guide roller being parallel to the take-up shaft; The vertical distances between the traction clamping roller, the first horizontal movable guide roller, the second horizontal movable guide roller, the third horizontal movable guide roller, the fourth horizontal movable guide roller, and the annular extrusion port increase sequentially. The traction clamping roller and the first horizontal movable guide roller are mounted on the first support, the second horizontal movable guide roller is mounted on the second support, the third horizontal movable guide roller is mounted on the third support, and the fourth horizontal movable guide roller is mounted on the fourth support. The first support, the second support, the third support, and the fourth support can all rotate horizontally around the central axis of the annular extrusion port. A bidirectional motor is also provided to drive the first support to rotate horizontally around the central axis of the annular extrusion port. A reduction transmission mechanism is provided between the first support and the second support, the third support, and the fourth support. The rotation angle ratio of the first support, the second support, the third support, and the fourth support is maintained at 4:3:2:

1. The second horizontal movable guide roller, the third horizontal movable guide roller, and the fourth horizontal movable guide roller are air cushion rollers. Each air cushion roller has a hollow roller cavity, air holes on the surface of each air cushion roller, an air inlet on the end face of the air cushion roller, and a fan to supply air to the air cushion roller. It is also equipped with photoelectric sensors for detecting the position of the left and right edges of the double-layer plastic film. The photoelectric sensors are located downstream of the horizontal fixed guide roller and upstream of the take-up shaft. It is also equipped with a central controller, and the photoelectric sensors are connected to the central controller. Its features are: The air holes on the surface of the fourth horizontal movable guide roller are divided into left and right halves. The air outlet of the air hole in the left half is inclined to the left, and the air outlet of the air hole in the right half is inclined to the right. The roller cavity of the fourth horizontal movable guide roller is divided into two isolated small chambers by a middle partition. The air inlet of the left small chamber is located on the left end face of the fourth horizontal movable guide roller, and the air inlet of the right small chamber is located on the right end face of the fourth horizontal movable guide roller. The air inlet of the left small chamber is connected to the left branch air inlet hose, and the air inlet of the right small chamber is connected to the right branch air inlet hose. The fan is connected to the left branch air inlet hose and the right branch air inlet hose through a main air supply pipe and an electromagnetic proportional valve.

2. The rotary traction blown film production equipment according to claim 1, characterized in that: The air outlet direction of the air holes on the surface of the fourth horizontal movable guide roller forms an angle of 45° to 65° with the central axis of the fourth horizontal movable guide roller.

3. A rotary traction blown film production process, using the rotary traction blown film production equipment as described in claim 1, comprising the following steps: The annular extrusion nozzle of the extrusion die continuously extrudes annular film bubbles. The film bubbles travel between two traction clamping rollers, and the annular film bubbles are flattened and folded by the two traction clamping rollers to form a double-layer plastic film. The double-layer plastic film then passes sequentially around the first horizontal movable guide roller, the second horizontal movable guide roller, the third horizontal movable guide roller, and the fourth horizontal movable guide roller, and reaches the horizontal fixed guide roller. When the double-layer plastic film reaches the horizontal fixed guide roller, its running direction is perpendicular to the horizontal fixed guide roller. After reaching the horizontal fixed guide roller, the double-layer plastic film continues to run and is finally wound up by the take-up shaft. During the above process, the bidirectional motor drives the first, second, third, and fourth supports to rotate periodically back and forth around the central axis of the annular extrusion port. The traction clamping roller, the first horizontal movable guide roller, and the first support rotate periodically back and forth synchronously. The second horizontal movable guide roller, the third horizontal movable guide roller, and the fourth horizontal movable guide roller rotate periodically back and forth synchronously. The rotation angle between the first horizontal movable guide roller and the traction clamping roller is maintained at 1:1, while the rotation angles of the first, second, third, and fourth horizontal movable guide rollers are maintained at 4:3:2:

1. When the first horizontal movable guide roller is parallel to the horizontal fixed guide roller, the second, third, and fourth horizontal movable guide rollers are also parallel to the horizontal fixed guide roller. During the above process, the fan continuously blows air into the roller cavities of the second and third horizontal movable guide rollers, and then the air is ejected from the air holes on the surface of the second and third horizontal movable guide rollers. The fan also supplies air to the main air supply pipe of the fourth horizontal movable guide roller. The air in the main air supply pipe of the fourth horizontal movable guide roller is distributed by the electromagnetic proportional valve into the left branch air inlet hose and the right branch air inlet hose. The air flowing into the left branch air inlet hose enters the left small chamber of the fourth horizontal movable guide roller through the air inlet on the left side of the fourth horizontal movable guide roller, and is finally ejected from the air hole on the left half of the fourth horizontal movable guide roller. The air flowing into the right branch intake hose enters the right small chamber of the fourth horizontal movable guide roller through the air inlet on the right side of the fourth horizontal movable guide roller, and is finally ejected from the air hole on the right half of the fourth horizontal movable guide roller. During the above process, the photoelectric sensor continuously detects the lateral position of the left and right edges of the double-layer plastic film and transmits the signal to the central controller. When the central controller determines that the lateral position of the double-layer plastic film has shifted to the left, the central controller uses the electromagnetic proportional valve to allocate more air to the right branch intake hose than to the left branch intake hose. When the central controller determines that the lateral position of the double-layer plastic film has shifted to the right, the central controller uses the electromagnetic proportional valve to allocate less air to the right branch intake hose than to the left branch intake hose. When the central controller determines that the lateral position of the double-layer plastic film has not shifted, the central controller uses the electromagnetic proportional valve to allocate the same amount of air to the right branch intake hose as to the left branch intake hose.

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