A packaging bag film blowing system

Abstract

The application provides a packaging bag film blowing system, which comprises a fan, a wind ring assembly and a discharge die head, the wind ring assembly comprises a base and an upper air disc, the base is installed on the discharge die head, the upper air disc covers the base, and a lower air lip is fixedly connected to the upper air disc; a main air channel is formed between the base, the upper air disc and the lower air lip, a lower air channel is formed between the base and the lower air lip, and the lower air channel communicates with the main air channel; a first upper air channel and a second upper air channel are arranged on the lower air lip, an annular groove is arranged on the lower air lip, a first air hole is arranged on the annular groove, a blocking ring is slidably installed in the annular groove, and a second air hole is arranged on the blocking ring; the application can solve the problem that the air port of the wind ring in the prior art is in an open state for a long time, dust in the air easily enters the inside of the wind ring device through the air port, the dust is blown to the film tube which has not been completely cooled by the cooling air, and the film quality is seriously affected.

Description

A blown film system for packaging bags Technical Field

[0001] This invention relates to the field of bag forming technology, specifically to a blown film system for packaging bags and its forming method. Background Technology

[0002] The production of plastic bags primarily utilizes blown film machines, which heat and melt plastic particles before blowing them into a thin film. The machine mainly consists of an extruder, die head, mold head, cooling device, bubble stabilizer, herringbone plate, traction rollers, and winding device. The workflow is as follows: dried polyethylene particles are added to the hopper and, by their own weight, enter the screw. When the particles contact the screw's beveled edges, the rotating beveled surfaces exert a thrust perpendicular to the beveled surfaces, propelling the plastic particles forward. During this movement, friction occurs between the plastic and the screw, between the plastic and the barrel, as well as collisions and friction between the particles, and the external heating of the barrel gradually melts the plastic. The molten plastic is filtered through the die head to remove impurities and exits through the mold head. It is then cooled by the air ring, passed through the bubble stabilizer, inflated by the herringbone plate and traction rollers, and finally wound into a roll by the winding machine.

[0003] Currently, cooling air rings used for blown film come in various forms, including single-outlet and double-outlet types. Their purpose is to provide uniform and sufficient cooling to the film bubble, reduce the impact of cooling air on film thickness, and improve film thickness. In actual production, after the air ring provides uniform cooling air around the circumference, the film thickness often depends on the design and manufacturing level of the mold. However, the existing device has a simple locking structure, which causes air leakage and seriously affects work efficiency. To address the problems existing in the prior art, CN214188436U discloses a high-pressure dual-outlet air ring for degradable membranes, comprising a base with a cavity. A drive locking device is installed within the cavity. A first through hole is formed in the upper wall of the cavity, and the drive end of the drive locking device passes through the first through hole. A support rod is fixedly installed on the upper wall of the base, located on one side of the first through hole. A locking plate is hinged to the support rod, with one end of the locking plate hinged to the drive end of the drive locking device and the other end of the locking plate snapped with a top cover. A main air duct is provided between the top cover and the base. A protruding ring is fixedly installed at the center of the base, and an air outlet device is installed between the top cover and the protruding ring. Several second through holes are formed on the base, and several air inlets are fixedly connected to the lower ends of the second through holes.

[0004] Although the prior art 1 improves the safety of the air ring during use by setting a locking device, the air vent of the air ring in the prior art 1 is always in an open state. Dust in the air can easily enter the interior of the air ring device through the air vent. After the dust accumulates inside the air ring device, it will be carried by the cooling air and blown onto the film tube that has not been completely cooled. Since the outer surface of the film tube that has not been completely cooled is still in a molten state, the dust will seriously affect the film formation quality of the film tube after adhering to the surface of the film tube. Summary of the Invention

[0005] The purpose of this invention is to provide a blown film system for packaging bags, which, in practical use, can solve the problem in the prior art where the air vents of the air ring are always open, allowing dust in the air to easily enter the interior of the air ring device through the vents. The dust is then carried by the cooling air and blown onto the film tube that has not yet been fully cooled, seriously affecting the film quality.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A blown film system for packaging bags includes a blower, an air ring assembly, and a discharge die head. The air ring assembly includes a base and an upper air plate. The base is installed on the discharge die head, and the upper air plate covers the base. A lower air lip is fixedly connected to the upper air plate. A main air duct is formed between the base, the upper air plate, and the lower air lip. A lower air duct is formed between the base and the lower air lip. The lower air duct is connected to the main air duct.

[0008] The lower lip is provided with a first upper air duct and a second upper air duct. The lower lip is provided with an annular groove. The annular groove is provided with a first air hole. A baffle ring is slidably installed in the annular groove. The baffle ring is provided with a second air hole. The first upper air duct and the second upper air duct can both be connected to the main air duct through the first air hole and the second air hole.

[0009] A limiting groove is provided on the lower air lip, and a limiting component is provided on the baffle ring to limit the baffle ring in conjunction with the limiting groove. A sealing component for sealing the lower air duct is installed in the limiting groove, and the fan is used to supply air into the main air duct.

[0010] Preferably, the sealing assembly includes a first airbag, a second airbag, and an air tube. The first airbag is installed at the bottom of the annular groove, the second airbag is connected to the end of the downdraft near the limiting groove, and the first airbag is connected to the second airbag through the air tube.

[0011] Preferably, an air guide component is fixedly connected to the lower air lip.

[0012] Preferably, the air guide assembly includes an inner air lip and an outer air lip, the inner air lip is fixedly connected to the lower air lip, the outer air lip is rotatably fitted onto the inner air lip, and the outer air lip and the inner air lip are threadedly connected.

[0013] Preferably, the inner air lip is provided with a plurality of first air holes, and the outer air lip is provided with a plurality of second air holes corresponding to the first air holes.

[0014] Preferably, the outer lip is threaded with a locking bolt.

[0015] Preferably, a rubber pad is rotatably installed on the side of the locking bolt near the inner air lip.

[0016] Preferably, the limiting component includes a first spring and a mounting base. A ball bearing corresponding to the limiting groove is rotatably mounted in the mounting base. A placement groove is provided on the retaining ring. The mounting base is connected to the placement groove through the first spring.

[0017] Preferably, the fan is connected to an air inlet pipe, the end of the air inlet pipe away from the fan is connected to the main air duct, and a filter screen is installed inside the air inlet pipe.

[0018] Preferably, a guide tube is detachably installed on the discharge die head.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] In this invention, there are four limiting grooves and two first air holes, each corresponding to a first upper air duct and a second upper air duct, respectively. The first upper air duct is positioned above the second upper air duct, and the air outlet angles of the first and second upper air ducts are different. There are also two second air holes. When the baffle ring moves vertically up and down, the second air holes cooperate with the baffle ring to control the opening and closing of the first upper air duct, the second upper air duct, and the lower air duct. When the limiting component on the baffle ring cooperates with the lowermost limiting groove to limit the baffle ring, neither of the two first air holes can communicate with the first and second upper air ducts through the two second air holes on the baffle ring. At this time, the baffle ring simultaneously blocks both the first and second upper air ducts, thereby preventing dust from the cooling air from entering the main air duct through the first and second upper air ducts. Furthermore, as the baffle ring moves vertically downward to the position corresponding to the lowest limiting groove, the sealing component installed in the limiting groove contacts the bottom end of the baffle ring and is squeezed by the baffle ring, thus blocking the lower air duct. When the limiting component installed on the baffle ring contacts and cooperates with the lowest limiting groove to limit and fix the baffle ring, the sealing component can continuously block the lower air duct under the squeezing of the baffle ring, thereby preventing dust from entering the main air duct with the cooling airflow through the lower air duct.

[0021] When the limiting component on the baffle ring cooperates with the second limiting groove from the bottom to limit the baffle ring, the first air hole located at the top is connected to the first upper air duct through the second air hole located at the top, and the first air hole located at the bottom is not connected to the second upper air duct due to the obstruction of the baffle ring; after the baffle ring moves up, it no longer squeezes the sealing component in the limiting groove, and the sealing component no longer blocks the lower air duct;

[0022] When the limiting component on the baffle ring cooperates with the third limiting groove from the bottom to limit the baffle ring, the first air hole located below is connected to the second upper air duct through the second air hole located below, and the first air hole located above is not connected to the first upper air duct due to the obstruction of the baffle ring; after the baffle ring moves up, it no longer squeezes the sealing component in the limiting groove, and the sealing component no longer blocks the lower air duct;

[0023] When the limiting component on the baffle ring cooperates with the uppermost limiting groove to limit the baffle ring, neither of the two first air holes can connect with the first and second upper air ducts through the two second air holes on the baffle ring. Furthermore, after the baffle ring moves upward, it no longer squeezes the sealing component in the limiting groove, and the sealing component no longer blocks the lower air duct. By moving the baffle ring, the selection of the first and second upper air ducts can be achieved, and the first, second, and lower air ducts connected to the main air duct can be blocked simultaneously. This satisfies the cold air outlet angle requirements of different diameter film tubes, and also prevents dust from entering the main air duct when the blow molding machine is not working. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 is a schematic diagram of the connection relationship between the lower wind lip and the upper wind plate in this invention.

[0026] Figure 2 is a schematic diagram of the structure of the present invention.

[0027] Figure 3 is a partial enlarged view of point A in Figure 2 of this invention.

[0028] The attached diagram lists the components represented by each number as follows:

[0029] 101-Air ring assembly, 102-Discharge die head, 103-Base, 104-Upper air plate, 105-Lower air lip, 106-Lower air duct, 107-Main air duct, 108-First upper air duct, 109-Second upper air duct, 110-Annular groove, 111-First air hole, 112-Baffle ring, 113-Second air hole, 114-Limiting groove, 115-Limiting assembly, 116-Blocking assembly, 117-First airbag, 118-Second airbag, 119-Air pipe, 120-Air guide assembly, 121-Inner air lip, 122-Outer air lip, 123-First exhaust hole, 124-Second exhaust hole, 125-Locking bolt, 126-First spring, 127-Mounting seat, 128-Ball bearing, 129-Air inlet pipe, 130-Diaphragm guide tube. Detailed Implementation

[0030] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0031] In the description of the embodiments of the present invention, it should be understood that the terms "length", "vertical", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention according to the specific circumstances.

[0034] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] The following disclosure provides many different implementations or examples for carrying out different structures of the embodiments of the present invention. To simplify the disclosure of the embodiments of the present invention, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the embodiments of the present invention. Furthermore, reference numerals and / or reference letters may be repeated in different examples of the embodiments of the present invention; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0036] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0037] Example 1

[0038] Referring to Figures 1-3, this embodiment discloses a blown film system for packaging bags, specifically a blown film blowing device, including a blower, a blown film assembly 101, and a discharge die head 102. The blown film assembly 101 includes a base 103 and an upper air plate 104. The base 103 is mounted on the discharge die head 102, and the upper air plate 104 covers the base 103. A lower air lip 105 is fixedly connected to the upper air plate 104. A main air duct 107 is formed between the base 103, the upper air plate 104, and the lower air lip 105. A lower air duct 106 is formed between the base 103 and the lower air lip 105, and the lower air duct 106 is connected to the main air duct 107. A first upper air duct 108 and a second upper air duct 105 are provided on the lower air lip 105. The air duct 109 has an annular groove 110 on its lower air lip 105, a first air hole 111 on the annular groove 110, a baffle ring 112 slidably installed in the annular groove 110, and a second air hole 113 on the baffle ring 112. The first upper air duct 108 and the second upper air duct 109 can both communicate with the main air duct 107 through the first air hole 111 and the second air hole 113. The lower air lip 105 has a limiting groove 114, and the baffle ring 112 has a limiting component 115 for limiting the baffle ring 112 in cooperation with the limiting groove 114. A blocking component 116 for blocking the lower air duct 106 is installed in the limiting groove 114. The fan is used to supply air into the main air duct 107.

[0039] In this invention, there are four limiting grooves 114, and two first air holes 111, which correspond to the first upper air duct 108 and the second upper air duct 109 respectively. The first upper air duct 108 is located above the second upper air duct 109, and the air outlet angles of the first upper air duct 108 and the second upper air duct 109 are different. There are two second air holes 113. When the baffle ring 112 moves vertically up and down, the second air holes 113 are used to cooperate with the baffle ring 112 to control the opening and closing of the first upper air duct 108, the second upper air duct 109, and the lower air duct 106. When the limiting component 115 on the baffle ring 112 cooperates with the lowermost limiting groove 114 to control the baffle ring 112... When the limit is applied, neither of the two first air holes 111 can connect with the first upper air duct 108 and the second upper air duct 109 through the two second air holes 113 provided on the baffle ring 112. At this time, the baffle ring 112 simultaneously blocks both the first upper air duct 108 and the second upper air duct 109, thereby preventing cooling air dust from entering the main air duct 107 through the first upper air duct 108 and the second upper air duct 109. Furthermore, when the baffle ring 112 moves vertically downward to the position corresponding to the lowest limiting groove 114, the sealing component 116 installed in the limiting groove 114 contacts the bottom end of the baffle ring 112 and, after being squeezed by the baffle ring 112, can block the lower air duct 106. After the limiting component 115 mounted on the baffle ring 112 contacts and engages with the lowermost limiting groove 114 to limit and fix the baffle ring 112, the sealing component 116 can continuously block the lower air duct 106 under the compression of the baffle ring 112, thereby preventing dust from entering the main air duct 107 through the lower air duct 106 with the cooling airflow; when the limiting component 115 mounted on the baffle ring 112 engages with the second limiting groove 114 from the bottom to limit the baffle ring 112, the upper first air hole 111 communicates with the first upper air duct 108 through the upper second air hole 113, and the lower first air hole 111 is blocked by the baffle ring 112 and does not communicate with the second upper air duct 108. The passage 109 is connected; after the baffle ring 112 moves upward, it no longer presses against the sealing component 116 in the limiting groove 114, and the sealing component 116 no longer blocks the downdraft passage 106; when the limiting component 115 on the baffle ring 112 cooperates with the third limiting groove 114 from the bottom to limit the baffle ring 112, the first air hole 111 located below is connected to the second updraft passage 109 through the second air hole 113 located below, and the first air hole 111 located above is not connected to the first updraft passage 108 due to the obstruction of the baffle ring 112; after the baffle ring 112 moves upward, it no longer presses against the sealing component 116 in the limiting groove 114, and the sealing component 116 no longer blocks the downdraft passage 106;When the limiting component 115 on the baffle ring 112 cooperates with the uppermost limiting groove 114 to limit the baffle ring 112, neither of the two first air holes 111 can connect with the first upper air duct 108 and the second upper air duct 109 through the two second air holes 113 on the baffle ring 112. Furthermore, after the baffle ring 112 moves upward, it no longer presses against the sealing component 116 in the limiting groove 114, and the sealing component 116 no longer blocks the lower air duct 106. By moving the baffle ring 112, the selection of the first upper air duct 108 and the second upper air duct 109 can be achieved, and the first upper air duct 108, the second upper air duct 109, and the lower air duct 106 connected to the main air duct 107 can be blocked simultaneously. This satisfies the requirements of different diameter film tubes for the cold air outlet angle while also preventing dust from entering the main air duct 107 when the blow molding machine is not working.

[0040] The sealing component 116 includes a first airbag 117, a second airbag 118, and an air tube 119. The first airbag 117 is installed at the bottom end of the annular groove 110, and the second airbag 118 is connected to the end of the downdraft duct 106 near the limiting groove 114. The first airbag 117 is connected to the second airbag 118 through the air tube 119. When the baffle ring 112 moves vertically downward to the position corresponding to the lowest limiting groove 114, the first airbag 117 contacts the bottom end of the baffle ring 112 and is squeezed by the baffle ring 112. The gas in the first airbag 117 enters the second airbag 118 through the air tube 119. After the second airbag 118 expands, it can block the downdraft duct 106, preventing dust from entering the main air duct 107 through the downdraft duct 106. When the limiting component 115 set on the baffle ring 112 is matched with the second limiting groove 114 from the bottom, the sealing component 117 can also block the downdraft duct 106. When the retaining ring 112 is positioned, its bottom end no longer contacts the first airbag 117. After the gas in the second airbag 118 returns to the first airbag 117 through the air pipe 119, the second airbag 118 no longer blocks the lower air duct 106. In this embodiment, the volume of the first airbag 117 is larger than the volume of the second airbag 118, and both the first and second airbags 117 and 118 are made of thin, stretchable rubber. The second airbag 118 is fixedly bonded to the end of the lower air duct 106 near the limiting groove 114.

[0041] Example 2

[0042] Referring to Figures 1-3, this embodiment is a further optimization based on Embodiment 1, with a guide air assembly 120 fixedly connected to the lower air lip 105. The guide air assembly 120 is used to guide the cooling air blown out of the lower air duct 106, the first upper air duct 108, and the second upper air duct 109 to the membrane tube, so that more cold air can be in contact with the membrane tube for a longer time, which is beneficial to the cooling of the membrane tube.

[0043] The air guide assembly 120 includes an inner air lip 121 and an outer air lip 122. The inner air lip 121 is fixedly connected to the lower air lip 105, and the outer air lip 122 is rotatably fitted onto the inner air lip 121. The outer air lip 122 is threadedly connected to the inner air lip 121. Rotating the outer air lip 122, which is threadedly connected to the inner air lip 121, allows the outer air lip 122 to move vertically upward. By raising the outer air lip 122, the cooling airflow path to the diaphragm tube can be increased. The cooling path and effect of the diaphragm tube can be adjusted according to the actual needs of changes in ambient temperature.

[0044] Further optimization involves providing several first exhaust holes 123 on the inner lip 121 and several second exhaust holes 124 on the outer lip 122 that correspond to the first exhaust holes 123. When the outer lip 122 is not rotated, the second air outlet 124 on the outer lip 122 is aligned with the first air outlet 123 on the inner lip 121. The amount of cold air emitted through the first air outlet 123 and the second air outlet 124 is maximized, which in turn reduces the amount of cold air flowing through the membrane tube. When the second air outlet 124 on the outer lip 122 is misaligned with the first air outlet 123 on the inner lip 121, the amount of cold air emitted through the first air outlet 123 and the second air outlet is reduced. The vertically upward-moving outer lip 122 also allows more cold air to flow upward through the membrane tube before being emitted. By rotating the relative positions of the inner lip 121 and the outer lip 122, the amount of cold air flowing through the membrane tube can be adjusted.

[0045] The outer lip 122 is threaded with a locking bolt 125. After the outer lip 122 is rotated to the preset position, the locking bolt 125 is rotated to tighten it onto the surface of the inner lip 121, thereby fixing the outer lip 122 and preventing it from rotating slightly under the influence of airflow and other external factors.

[0046] Further optimization involves rotatably mounting a rubber pad on the side of the locking bolt 125 near the inner lip 121. The rubber pad is rotatably mounted on the locking bolt 125 via a bearing. Rotating the rubber pad on the side of the inner lip 121 prevents the locking bolt 125 from scratching the surface of the inner lip 121 during the process of tightening the outer lip 122 by rotating the locking bolt 125.

[0047] The limiting component 115 includes a first spring 126 and a mounting base 127. A ball bearing 128, corresponding to the limiting groove 114, is rotatably mounted in the mounting base 127 via a bearing. A placement groove is provided on the retaining ring 112, and the mounting base 127 is connected to the placement groove via the first spring 126. A retaining groove is provided in the mounting base 127, and the ball bearing 128 is engaged in the mounting base 127. When the mounting base 127 moves with the retaining ring 112 to the position corresponding to the limiting groove 114, the ball bearing 128 is pressed into the limiting groove 114 under the action of the first spring 126, thereby limiting and fixing the retaining ring 112.

[0048] Further optimization involves connecting an air inlet pipe to the fan, with the end of the air inlet pipe furthest from the fan connected to the main air duct 107. A filter screen is installed inside the air inlet pipe. By installing a filter screen inside the air inlet pipe, dust in the cooling air can be prevented from entering the main air duct 107, and dust in the cooling air can be prevented from adhering to the incompletely cooled membrane tube.

[0049] The discharge die head 102 is detachably equipped with a film guide tube 130. By replacing the film guide tube 130 with different shapes, the diameter of the prepared film tube can be adjusted according to the actual situation.

[0050] Example 3

[0051] Referring to Figures 1-3, this embodiment is basically the same as Embodiment 1, except that in this embodiment, the blocking assembly 116 includes a second spring and a baffle. The baffle is slidably installed in the limiting groove 114, and a limiting platform is provided at one end of the stop located in the limiting groove 114. The limiting platform is connected to the limiting groove 114 through the second spring. During the process of the baffle ring 112 moving vertically downward to the position corresponding to the lowest limiting groove 114, the baffle installed in the limiting groove 114 contacts the bottom end of the baffle ring 112. After the baffle ring 112 is squeezed, it moves vertically downward until the bottom end of the baffle contacts the inner wall of the lower air duct 106, thereby blocking the lower air duct 106 and preventing dust from entering the main air duct 107 with the cooling airflow through the lower air duct 106. The elastic potential energy of the second spring is much smaller than that of the first spring 126. When the limiting component 115 set on the baffle ring 112 cooperates with the second limiting groove 114 from the bottom to limit the baffle ring 112, the baffle ring 112, after moving upward, no longer squeezes the baffle in the limiting groove 114. After the baffle moves vertically upward under the action of the second spring, it no longer blocks the lower air duct 106.

[0052] A pressure plate is connected to the retaining ring 112. By setting the pressure plate, the retaining ring 112 can be driven to move vertically up and down more effortlessly.

[0053] Further optimization involves installing a push rod on the outer air lip 122. This push rod allows for easier rotation of the outer air lip 122.

[0054] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A blown film system for packaging bags, comprising a blower, characterized in that: It also includes an air ring assembly (101) and a discharge die head (102). The air ring assembly (101) includes a base (103) and an upper air plate (104). The base (103) is mounted on the discharge die head (102), and the upper air plate (104) covers the base (103). A lower air lip (105) is fixedly connected to the upper air plate (104). A main air duct (107) is formed between the base (103), the upper air plate (104), and the lower air lip (105). A lower air duct is formed between the base (103) and the lower air lip (105). The downwind duct (106) is connected to the main air duct (107); the downwind lip (105) is provided with a first upwind duct (108) and a second upwind duct (109); the downwind lip (105) is provided with an annular groove (110); the annular groove (110) is provided with a first air hole (111); a baffle ring (112) is slidably installed in the annular groove (110); the baffle ring (112) is provided with a second air hole (113); the first upwind duct (108) and the second upwind duct (109) can both pass through the first air hole. (111) and the second air vent (113) are connected to the main air duct (107); a limiting groove (114) is provided on the lower air lip (105), and a limiting component (115) is provided on the baffle ring (112) to limit the baffle ring (112) in cooperation with the limiting groove (114). A sealing component (116) for sealing the lower air duct (106) is installed in the limiting groove (114). The fan is used to supply air into the main air duct (107); when the baffle ring (112) moves vertically up and down, the second air vent (113) is used to... The first upper air duct (108), the second upper air duct (109), and the lower air duct (106) are controlled in conjunction with the baffle ring (112); the sealing assembly (116) includes a first airbag (117), a second airbag (118), and an air tube (119). The first airbag (117) is installed at the bottom end of the annular groove (110), the second airbag (118) is connected to the end of the lower air duct (106) near the limiting groove (114), and the first airbag (117) is connected to the second airbag (118) through the air tube (119).

2. The packaging bag blown film system according to claim 1, characterized in that: An air guide assembly (120) is fixedly connected to the lower air lip (105).

3. The packaging bag blown film system according to claim 2, characterized in that: The air guide assembly (120) includes an inner air lip (121) and an outer air lip (122). The inner air lip (121) is fixedly connected to the lower air lip (105), and the outer air lip (122) is rotatably fitted onto the inner air lip (121). The outer air lip (122) is threadedly connected to the inner air lip (121).

4. The packaging bag blown film system according to claim 3, characterized in that: The inner lip (121) is provided with a number of first exhaust holes (123), and the outer lip (122) is provided with a number of second exhaust holes (124) corresponding to the first exhaust holes (123).

5. The packaging bag blown film system according to claim 4, characterized in that: The outer lip (122) is threaded with a locking bolt (125).

6. The packaging bag blown film system according to claim 5, characterized in that: A rubber pad is rotatably mounted on the side of the locking bolt (125) near the inner lip (121).

7. The packaging bag blown film system according to claim 1, characterized in that: The limiting component (115) includes a first spring (126) and a mounting base (127). A ball bearing (128) corresponding to the limiting groove (114) is rotatably mounted in the mounting base (127) through a bearing. A placement groove is provided on the retaining ring (112). The mounting base (127) is connected to the placement groove through the first spring (126).

8. A blown film system for packaging bags according to claim 1, characterized in that: The fan is connected to an air inlet pipe. The end of the air inlet pipe away from the fan is connected to the main air duct (107). A filter screen is installed inside the air inlet pipe.

9. A blown film system for packaging bags according to claim 1, characterized in that: A guide tube (130) is detachably installed on the discharge die head (102).

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