Plastic film blow molding equipment and method
By designing an airflow closing and air equalization mechanism in the film blow molding equipment and combining the suction ring for airflow cooling, the deformation and uneven forming problems caused by uneven wind force during film forming in the prior art are solved, and a more uniform cooling effect is achieved.
Patent Information
- Application Number
- CN202510524378.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-24
- Publication Date
- 2025-05-30
AI Technical Summary
The cooling equipment of existing film blowing equipment is blown through an annular air outlet, which may cause wind force to squeeze the film, causing uneven film thickness and molding.
A plastic film blow molding equipment is designed, including an extrusion base, a film head, an inflatable port, a sleeve, an air supply ring, a sleeve, a second and an intake sleeve ring. The airflow retraction mechanism and air equalization mechanism adjust the blowing height and uniformity of the airflow to the film, and the airflow is cooled by the suction ring to avoid direct blowing.
By adjusting the closing position and uniform distribution of the airflow, the deformation and uneven forming of the film due to uneven wind force is avoided, and a more uniform cooling effect is achieved.
Smart Images
Figure CN120056422A_ABST
Abstract
Description
Technical Field
[0001] Embodiments of the present disclosure relate to the technical field of film blowing, and more particularly, to a plastic film blowing device and method. Background Art
[0002] Film blowing is a common plastic processing technique mainly used for producing plastic films. Plastic film blowing is formed through steps such as extrusion, inflation, and cooling. A blowing machine consists of an extruder, a die head, an inflation system, a cooling system, a traction system, a winding system, and a control system, and is widely used in fields such as packaging, agriculture, and construction. During blowing, the raw material is conveyed to the die head through the extruder, and one end of the raw material extruded at the die head by the extruder is pulled to the traction device. The film is stretched by the traction device. Meanwhile, a cooling and shaping device is provided at the die head to blow air to shape the extruded plastic film. An inflation port is provided in the center of the die head, and the inflation port inflates the inside of the plastic film to keep the plastic film in a bubble-like expansion. At this time, the size of the plastic film is fixed, and then it passes through a chevron frame and a squeezing roller to be flattened and wound.
[0003] Most of the existing cooling devices on film blowing equipment cool the film by means of an annular air outlet sleeved on the die head, and the air outlet cools the film by blowing air circumferentially. However, only through the annular air outlet at the bottom, the wind force may cause extrusion to the film, resulting in stretching of the film, and uneven thickness and degree may occur at different positions of the film, making the shaping of the film more susceptible to influence. Summary of the Invention
[0004] To overcome the above defects, embodiments of the present disclosure provide a plastic film blowing device and method, which solve the technical problem that the blown air force is uneven during cooling and causes film deformation during the forming of plastic films in the prior art.
[0005] According to one aspect, at least one embodiment of the present disclosure provides a plastic film blowing device, including an extrusion base, above which a film head is arranged. The film head is communicated with an external extruder. An inflation port is arranged at the center of the film head and is communicated with an external air pump. The device further includes a sleeve one, a blowing air ring, a sleeve two and a suction collar. The sleeve one is sleeved on the extrusion base. An air distribution mechanism and an air flow converging mechanism are arranged in the sleeve one. The air flow converging mechanism is sleeved on the film head, and the air distribution mechanism is arranged below the air flow converging mechanism. The blowing air ring is sleeved on the extrusion base on the side away from the film head. An opening is arranged on the blowing air ring on the side close to the sleeve one, and the blowing air ring is communicated with an external blower. The air flow converging mechanism is used to adjust the converging position of the air flow blowing the film. The sleeve two is fixedly connected to the sleeve one and is arranged on the side of the sleeve one away from the blowing air ring. A film protection mechanism is arranged on the sleeve two and is used to wrap and protect the film. The suction collar is fixedly connected to one end of the sleeve two away from the blowing air ring and is communicated with an external suction pump. A gap is left between the sleeve one and the blowing air ring.
[0006] The air flow converging mechanism includes an annular bracket and a guide pipe. The annular bracket is fixedly connected in the sleeve one and is sleeved on the extrusion base. A plurality of fan-shaped through holes are circumferentially formed on the annular bracket. A plurality of guide pipes are arranged, and the plurality of guide pipes are sleeved with each other. A plurality of strip grooves are formed on the guide pipe, and the strip grooves are slidably connected with the annular bracket.
[0007] A conical closing opening is arranged on the side of the guide pipe close to the sleeve two. A limiting tooth is arranged on the side of the strip groove. A limiting plate is slidably connected to the annular bracket. The limiting plate penetrates through the strip grooves on the plurality of guide pipes. When the limiting plate contacts the limiting tooth, the guide pipe is fixed on the annular bracket.
[0008] The air distribution mechanism is used to evenly distribute the air flow entering the sleeve one. The air distribution mechanism includes a conical groove and a fan-shaped diversion chamber. The conical groove is arranged in a ring shape and is formed on the sleeve one on the side close to the blowing air ring. The side of the conical groove close to the air flow converging mechanism is a conical opening. The fan-shaped diversion chamber is communicated with the conical groove. A plurality of diversion sheets are arranged in the conical groove. In the fan-shaped diversion chamber, the plurality of diversion sheets are arranged at equal angles.
[0009] The sleeve two is arranged in a fan shape, and a plurality of arc-shaped rods are fixedly connected to the sleeve two. The plurality of arc-shaped rods are respectively arranged at both ends of the sleeve.
[0010] The film protection mechanism includes a protection plate, a toothed ring, a motor and a transmission shaft. The protection plate is set in a fan shape. The protection plate is sleeved on the second sleeve. A toothed ring is fixedly connected to the outer side of the protection plate. The motor is fixedly installed on the second sleeve. The transmission shaft is rotatably arranged on the second sleeve. The transmission shaft is in transmission connection with the output end of the motor. A gear is fixedly connected to the transmission shaft. The gear meshes with the toothed ring.
[0011] Two arc-shaped rings are fixedly connected to one side of the inner side of the protection plate. The arc-shaped rings are slidably connected to the arc-shaped rods. The protection plate is sleeved on the outer side of the second sleeve. The fan-shaped angle of the protection plate is larger than the fan-shaped angle of the second sleeve.
[0012] A plastic film blowing method, according to the above-mentioned plastic film blowing equipment, includes the following steps: Step 1, raw material traction: The die head extrudes the raw material, and the raw material is tractioned upward at the second sleeve and moves to the traction device, and the traction device pulls the film upward. Step 2, air flow convergence adjustment: Slide a plurality of the air guide pipes out to a suitable height respectively, and slide the limit plate into the limit teeth. The height at which the air guide pipes extend is fixed. Step 3, film sealing: The output end of the motor drives the transmission shaft to rotate. The gear on the transmission shaft meshes with the toothed ring, driving the protection plate to rotate on the second sleeve. The protection plate and the second sleeve form a cylinder. Step 4, internal air supply: The external air pump supplies air into the first sleeve through the air supply ring, and the air inflation port supplies air into the film interior. Step 5, suction cooling: The gap between the expanded film and the suction collar is reduced. The external suction pump sucks air to the outside through the suction collar, and the gas enters the first sleeve through the conical groove.
[0013] The beneficial effects of the embodiments of the present disclosure are as follows: 1. In the present invention, by setting the air guide pipes, the blowing height of the air flow entering the second sleeve to the film can be adjusted. When the air guide pipes are lifted to a higher height, the air flow converges more towards the film at a higher position. When the air guide pipes are lifted to a lower height, the air flow entering the second sleeve flows more dispersedly and does not converge towards the film, and the blowing effect on the film is smaller. 2. In the present invention, by setting the suction collar, the gas flow in the second sleeve is made more uniform by sucking the gas wrapped around the film to drive the gas flow, thereby avoiding the film being stretched and deformed by the air flow when the air is blown onto the film. 3. In the present invention, by providing an air flow converging mechanism, the height at which the air flow is blown onto the film and the blowing effect can be adjusted. By providing a film protection mechanism, the air flow in the environment can be prevented from affecting the film, and at the same time, the gas is cooled by flowing through suction, avoiding the direct blowing of the gas. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following will briefly introduce the drawings required for the description of the embodiments of the present disclosure. Obviously, the drawings described below are only some exemplary embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the content of the exemplary embodiments of the present disclosure and these drawings.
[0015] Figure 1 is a schematic structural diagram of the whole in the present invention; Figure 2 is a schematic structural diagram of the whole from another perspective in the present invention; Figure 3 is a schematic internal sectional view of the first sleeve in the present invention; Figure 4 is a schematic partial internal sectional view of the first sleeve from another perspective in the present invention; Figure 5 is a schematic partial internal sectional view of the air supply ring cooperating with the first sleeve in the present invention; Figure 6 is a schematic partial internal sectional view of the suction collar cooperating with the second sleeve in the present invention.
[0016] In the figure: 1. Extrusion base; 2. Die head; 3. Inflation port; 4. First sleeve; 5. Air supply ring; 6. Second sleeve; 7. Suction collar; 8. Ring bracket; 9. Air duct; 10. Strip groove; 11. Conical closing; 12. Limit teeth; 13. Limit plate; 14. Conical groove; 15. Sector-shaped flow guide bin; 16. Flow guide piece; 17. Arc rod; 18. Protection plate; 19. Tooth ring; 20. Motor; 21. Transmission shaft; 22. Arc ring. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0017] The following will further elaborate on the present disclosure in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present disclosure, rather than limiting the present disclosure.
[0018] For the sake of simplicity of the drawings, only the parts related to the disclosure are schematically shown in each drawing, and they do not represent the actual structure of the product as a whole. In addition, for the sake of simplicity and easy understanding of the drawings, for components with the same structure or function in some drawings, only one of them is schematically shown, or only one of them is labeled. In this text, "one" not only means "only this one", but also can mean "more than one" situation, and "several" includes "two" and "more than two".
[0019] In this text, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "joined" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances.
[0020] In this disclosure, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature can include the direct contact between the first and second features, or can also include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.
[0021] In the description of this embodiment, the orientation or positional relationships such as "up", "down", "left", "right", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to this disclosure.
[0022] In addition, in the description of this application, the terms "first", "second", etc. are only used for distinguishing descriptions, and cannot be understood as indicating or implying relative importance.
[0023] Embodiment 1 As Figures 1 to 6As shown in the figure, it shows a plastic film blowing device in an embodiment of the present disclosure, including an extrusion base 1. Above the extrusion base 1, there is a die head 2. The die head 2 is connected to an external extruder. In the center of the die head 2, there is an inflation port 3, and the inflation port 3 is connected to an external air pump. It also includes a first sleeve 4, a blowing ring 5, a second sleeve 6, and a suction collar 7. The first sleeve 4 is sleeved on the extrusion base 1. In the first sleeve 4, there is an air distribution mechanism and an air flow converging mechanism. The air flow converging mechanism is sleeved on the die head 2, and the air distribution mechanism is arranged below the air flow converging mechanism. The blowing ring 5 is sleeved on one side of the extrusion base 1 away from the die head 2. On the side of the blowing ring 5 close to the first sleeve 4, there is an opening. The blowing ring 5 is connected to an external blower. The air flow converging mechanism is used to adjust the converging position of the air flow blowing the film. The second sleeve 6 is fixedly connected to the first sleeve 4. The second sleeve 6 is arranged on the side of the first sleeve 4 away from the blowing ring 5. On the second sleeve 6, there is a film protection mechanism, which is used to wrap and protect the film. The suction collar 7 is fixedly connected to one end of the second sleeve 6 away from the blowing ring 5. The suction collar 7 is connected to an external suction pump. There is a gap between the first sleeve 4 and the blowing ring 5. Through the suction collar 7, the external air can be inhaled into the first sleeve 4 and the second sleeve 6 through the air distribution mechanism in the first sleeve 4 to cool the film. When the air flow entering through suction flows, it will not gather at the air outlet to blow the film. The air flow will drive the air flow in the entire second sleeve 6 to flow and move towards the opening on the suction collar 7. Compared with the prior art of cooling by blowing air, the air flow is more uniform in this way and is not likely to cause the film to deform.
[0024] As Figures 1 to 4 shown, the air flow converging mechanism includes an annular bracket 8 and a guide air pipe 9. The annular bracket 8 is fixedly connected in the first sleeve 4. The annular bracket 8 is sleeved on the extrusion base 1. A plurality of fan-shaped through holes are circumferentially formed on the annular bracket 8. There are a plurality of guide air pipes 9. The plurality of guide air pipes 9 are sleeved with each other. A plurality of strip grooves 10 are formed on the guide air pipe 9. The strip grooves 10 are slidably connected to the annular bracket 8. On the side of the guide air pipe 9 close to the second sleeve 6, there is a tapered necking 11. A limiting tooth 12 is arranged on the side of the strip groove 10. A limiting plate 13 is slidably connected to the annular bracket 8. The limiting plate 13 passes through the strip grooves 10 on the plurality of guide air pipes 9. When the limiting plate 13 contacts the limiting tooth 12, the guide air pipe 9 is fixed on the annular bracket 8. In this embodiment, there are two guide air pipes 9. The guide air pipes 9 divide the annular bracket 8 into three annular regions. By sliding the guide air pipe 9, the air flow in different regions can contact the film at different distances from the die head 2, and it can be adjusted according to different environmental temperatures and different heat dissipation requirements of different materials. The tapered necking 11 can converge the air flow towards the center. By raising the guide air pipe 9, the air flow can be made to converge and blow towards the film at a position farther from the die head 2. The position of the guide air pipe 9 can be adjusted through the limiting plate 13 and the limiting tooth 12.
[0025] As Figures 3 to 4 shown, the air equalizing mechanism is used to evenly distribute the air flow entering the first sleeve 4. The air equalizing mechanism includes a conical groove 14 and a fan-shaped guide chamber 15. The conical groove 14 is arranged in a ring shape and is opened on one side of the first sleeve 4 close to the air supply ring 5. The side of the conical groove 14 close to the air flow converging mechanism is set as a conical opening. The fan-shaped guide chamber 15 is communicated with the conical groove 14. A plurality of guide vanes 16 are arranged in the conical groove 14. In the fan-shaped guide chamber 15, the plurality of guide vanes 16 are arranged at equal angles. After the air flow is converged by the conical groove 14, it flows into the gaps between the plurality of guide vanes 16 respectively, and then evenly flows to the annular bracket 8.
[0026] As Figure 2 and Figure 6 shown, the second sleeve 6 is arranged in a fan shape. A plurality of arc-shaped rods 17 are fixedly connected to the second sleeve 6. The plurality of arc-shaped rods 17 are respectively arranged at both ends of the sleeve. There are two arc-shaped rods 17 to ensure the rotation trajectory of the protection plate 18.
[0027] As Figures 1 to 2 shown, the film protection mechanism includes a protection plate 18, a toothed ring 19, a motor 20 and a transmission shaft 21. The protection plate 18 is arranged in a fan shape. The protection plate 18 is sleeved on the second sleeve 6. A toothed ring 19 is fixedly connected to the outer side of the protection plate 18. The motor 20 is fixedly installed on the second sleeve 6. The transmission shaft 21 is rotatably arranged on the second sleeve 6. The transmission shaft 21 is in transmission connection with the output end of the motor 20. The output end of the motor 20 is in transmission connection with the transmission shaft 21 through a gearbox. A gear is fixedly connected to the transmission shaft 21, and the gear meshes with the toothed ring 19.
[0028] As Figure 2 and Figure 6 shown, two arc-shaped rings 22 are fixedly connected to one side inside the protection plate 18. The arc-shaped rings 22 are slidably connected to the arc-shaped rods 17. The protection plate 18 is sleeved on the outer side of the second sleeve 6. The fan-shaped angle of the protection plate 18 is greater than the fan-shaped angle of the second sleeve 6. The angle of the protection plate 18 is greater than that of the second sleeve 6, so that both sides of the protection plate 18 cover the edges of the second sleeve 6 after rotation, enhancing the airtightness. By arranging the arc-shaped rings 22 on one side, the rotation of the protection plate 18 can be limited.
[0029] As Figures 5 to 6As shown, the suction collar 7 and the air supply collar 5 are both partitioned, and each zone is connected to the ventilation duct, so that the air flow can flow evenly. When blow molding starts, the film does not expand into a bubble-like state, and there is a gap between the film and the suction collar 7. To reduce the amount of air entering through the gap between the air supply collar and the film when the air supply collar sucks air, first, air is supplied into the sleeve one 4 through the air supply collar 5. When the inflation port 3 supplies air into the film and causes the film to expand, at this time, air can be sucked through the suction collar 7 so that the gas flows in the sleeve two 6. At the same time, the air inlet of the fan connected to the air supply collar 5 can be connected to a cooling device such as an air conditioner. When the room temperature is high, low-temperature gas can be introduced into the air supply collar 5, and the low-temperature gas enters the sleeve one 4 with the outside gas for cooling.
[0030] In some examples, the gas in the sleeve two 6 is evenly sucked away through the suction collar 7, avoiding the squeezing effect of the air flow on the film during direct blowing on the traditional cooling device. At the same time, the sleeve two 6 and the protective plate 18 can prevent the influence of the ambient air flow on the film.
[0031] Embodiment Two A method for blow molding a plastic film, according to the above-mentioned plastic film blow molding equipment, includes the following steps: Step 1, raw material traction: The die head 2 extrudes the raw material, and the raw material is tractioned upward at the sleeve two 6 to the traction device, and the film is pulled upward by the traction device; Step 2, air flow convergence adjustment: Slide a plurality of air ducts 9 out to the appropriate height respectively, and slide the limit plate 13 into the limit teeth 12, and the height at which the air ducts 9 extend is fixed; Step 3, film enclosure: The output end of the motor 20 drives the transmission shaft 21 to rotate, the gear on the transmission shaft 21 meshes with the toothed ring 19, driving the protective plate 18 to rotate on the sleeve two 6, and the protective plate 18 and the sleeve two 6 form a cylinder; Step 4, internal air supply: The external air pump supplies air into the sleeve one 4 through the air supply collar 5, and the inflation port 3 supplies air into the film; Step 5, suction cooling: The gap between the expanded film and the suction collar 7 shrinks, and the external suction pump sucks air to the outside through the suction collar 7, and the gas enters the sleeve one 4 through the tapered groove 14.
[0032] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure and are not restrictive. Although the present disclosure has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present disclosure can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present disclosure, and they should all be covered within the scope of the claims of the present disclosure.
Claims
1. A plastic film blow molding device, comprising an extrusion base (1), a film head (2) is arranged above the extrusion base (1), the film head (2) is connected to an external extruder, an air filling port (3) is arranged at the center of the film head (2), the air filling port (3) is connected to an external air pump, and is characterized in that: Also includes: Sleeve 1 (4), the sleeve 1 (4) is sleeved on the extrusion base (1), an air distribution mechanism and an air flow gathering mechanism are arranged in the sleeve 1 (4), the air flow gathering mechanism is sleeved on the membrane head (2), and the air distribution mechanism is arranged below the air flow gathering mechanism; An air supply ring (5), the air supply ring (5) being sleeved on a side of the extrusion base (1) away from the membrane head (2), an opening being provided on a side of the air supply ring (5) close to the sleeve (4), and the air supply ring (5) being connected to an external fan; The airflow gathering mechanism is used to adjust the gathering position of the airflow blowing on the film; Sleeve 2 (6), the sleeve 2 (6) is fixedly connected to the sleeve 1 (4), the sleeve 2 (6) is arranged on a side of the sleeve 1 (4) away from the air supply ring (5), and a film protection mechanism is arranged on the sleeve 2 (6), and the film protection mechanism is used to wrap and protect the film; An air suction ring (7) is fixedly connected to an end of the second sleeve (6) away from the air supply ring (5), and the air suction ring (7) is connected to an external air suction pump.
2. A plastic film blowing device according to claim 1, characterized in that: The airflow gathering mechanism comprises: an annular bracket (8), the annular bracket (8) being fixedly connected to the sleeve 1 (4), the annular bracket (8) being sleeved on the extrusion base (1), and the annular bracket (8) being provided with a plurality of fan-shaped through holes in a circumferential manner; An air guide tube (9), wherein a plurality of the air guide tubes (9) are provided, the plurality of the air guide tubes (9) are mutually sleeved, a plurality of grooves (10) are provided on the air guide tube (9), and the grooves (10) are slidably connected to the annular bracket (8).
3. A plastic film blowing device according to claim 2, characterized in that: A conical closing end (11) is provided on one side of the air guide tube (9) close to the second sleeve (6), and a limiting tooth (12) is provided on the side of the strip groove (10). A limiting plate (13) is slidably connected to the annular bracket (8), and the limiting plate (13) passes through a plurality of the strip grooves (10) on the air guide tube (9). When the limiting plate (13) contacts the limiting tooth (12), the air guide tube (9) is fixed on the annular bracket (8).
4. A plastic film blowing device according to claim 3, characterized in that: The air balancing mechanism is used to evenly distribute the airflow entering the sleeve 1 (4), and the air balancing mechanism includes: A conical groove (14), the conical groove (14) being arranged in an annular shape, the conical groove (14) being opened on a side of the sleeve (4) close to the air supply ring (5), and a side of the conical groove (14) close to the airflow gathering mechanism being arranged as a conical opening; A fan-shaped flow guide bin (15), the fan-shaped flow guide bin (15) being in communication with the conical groove (14), and a plurality of flow guide plates (16) being arranged in the conical groove (14).
5. A plastic film blowing device according to claim 4, characterized in that: In the fan-shaped guide chamber (15), a plurality of guide blades (16) are arranged at equal angles.
6. A plastic film blowing device according to claim 5, characterized in that: The second sleeve (6) is arranged in a fan shape, and a plurality of arc-shaped rods (17) are fixedly connected to the second sleeve (6), and the plurality of arc-shaped rods (17) are respectively arranged at both ends of the sleeve.
7. A plastic film blowing device according to claim 6, characterized in that: The film protection mechanism comprises: a protective plate (18), the protective plate (18) being arranged in a fan shape, and the protective plate (18) being sleeved on the second sleeve (6); A gear ring (19), the outer side of the protective plate (18) being fixedly connected to the gear ring (19); A motor (20), the motor (20) being fixedly mounted on the second sleeve (6); A transmission shaft (21), the transmission shaft (21) being rotatably disposed on the second sleeve (6), the transmission shaft (21) being transmission-connected to an output end of the motor (20), a gear being fixedly connected to the transmission shaft (21), and the gear being meshed with the gear ring (19).
8. A plastic film blowing device according to claim 7, characterized in that: Two arc-shaped rings (22) are fixedly connected to one side of the inner side of the protective plate (18), and the arc-shaped rings (22) are slidably connected to the arc-shaped rod (17). The protective plate (18) is sleeved on the outer side of the second sleeve (6), and the sector angle of the protective plate (18) is greater than the sector angle of the second sleeve (6).
9. A plastic film blowing device according to claim 8, characterized in that: A gap is left between the sleeve 1 (4) and the air supply ring (5).
10. A plastic film blowing method, according to the plastic film blowing equipment according to claim 9, characterized in that: The steps include: S1, raw material pulling: the film head (2) extrude the raw material, pull the raw material upward to the pulling device at the second position of the sleeve, and pull the film upward through the pulling device; S2, airflow gathering adjustment: sliding the plurality of air guide tubes (9) to extend to a suitable height respectively, sliding the limiting plate (13) to extend into the limiting tooth (12), and fixing the extending height of the air guide tubes (9); S3, film sealing: the output end of the motor (20) drives the transmission shaft (21) to rotate, the gear on the transmission shaft (21) meshes with the gear ring (19), driving the protective plate (18) to rotate on the second sleeve (6), and the protective plate (18) and the second sleeve (6) form a cylinder; S4, internal air supply: an external air pump supplies air to the sleeve 1 (4) through the air supply ring (5), and the air filling port (3) supplies air to the inside of the film; S5, air intake cooling: the film expands and the gap between it and the air intake ring (7) is reduced, and an external air intake pump sucks air to the outside through the air intake ring (7), and the gas enters the sleeve 1 (4) through the conical groove (14).