Plastic film processing equipment for improving film yield

Abstract

The present invention discloses a plastic film processing device for improving the yield rate of the film, comprising a machine head, a sealing part and a pressure-applying structure. An air inlet channel and a pressure relief channel are provided in the machine head, the air inlet channel is connected to the air source, the pressure relief channel is connected to the middle chamber, and the size of the middle chamber is larger than that of the pressure relief channel; the sealing part is located in the middle chamber, and the top surface of the sealing part abuts the outlet end of the pressure relief channel; the pressure-applying structure is used to apply pressure to the bottom surface of the sealing part. The provision of a pressure relief channel and a sealing part can achieve automatic pressure relief after the pressure value reaches a certain level. On the basis of effectively ensuring the stability of the pressure, the air supply rate can be increased. After the starting end of the plastic film is closed and sealed, the specified pressure value can be quickly reached and maintained stable, reducing the amount of non-standard plastic film at the starting end and reducing the waste of raw materials. At the same time, the blowing capacity of the plastic film can be increased to ensure the mechanical properties of the plastic film under stretching.

Description

Technical Field

[0001] The present invention relates to the technical field of film processing, and in particular to plastic film processing equipment for improving film yield. Background Art

[0002] Plastic film refers to films made from polyvinyl chloride, polyethylene, polypropylene, polystyrene, and other resins, used for packaging and as a coating. The plastic film industry uses two production methods: calendaring and extrusion. Extrusion is further divided into blown film, cast film, and stretch film (also known as secondary molding). Extrusion is the most widely used, especially for the processing of polyolefin films, while calendaring is primarily used in the production of some polyvinyl chloride films.

[0003] Among them, the film blowing machine is a mechanical equipment that blows heated and molten plastic into a film; the molten plastic comes out from the die through the machine head, is blown and cooled by the air ring, and then pressed by the herringbone plate, and is wound by the traction roller to roll the finished film into a tube.

[0004] During the film inflation process, in order to ensure the uniformity of film inflation and thus ensure the quality of the film's mechanical properties, it is necessary to ensure the stability of the pressure inside the film in the inflated state. In order to ensure the stability of the pressure and facilitate regulation, the rate of introducing gas into the film for inflation is greatly limited, and gas can only be introduced relatively slowly to ensure relative stability of the pressure. This results in a longer time to increase the pressure, inflate and regulate the pressure during the initial extrusion of the film, which in turn results in the film raw materials at the starting end being unable to meet the quality requirements, resulting in a large amount of raw material waste. Summary of the Invention

[0005] The technical problem solved by the present invention is: during the film inflation process, in order to ensure the uniformity of film inflation and thus ensure the quality of the film's mechanical properties, it is necessary to ensure the stability of the pressure inside the film in the inflated state. In order to ensure the stability of the pressure, the rate at which gas is introduced into the film for inflation is greatly limited, and gas can only be introduced relatively slowly to ensure relative stability of the pressure. This results in a longer time required to increase the pressure and inflate the film during the initial extrusion, which in turn results in the film raw materials at the starting end being unable to meet the quality requirements, resulting in a large amount of waste of raw materials.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A plastic film processing device for improving film yield, comprising:

[0008] A handpiece, wherein an air inlet channel and a pressure relief channel are formed in the handpiece, the air inlet channel is connected to an air source, the pressure relief channel is connected to an intermediate chamber, and the size of the intermediate chamber is larger than that of the pressure relief channel;

[0009] a blocking portion, the blocking portion being located in the intermediate chamber, the top surface of the blocking portion abutting against the outlet end of the pressure relief channel;

[0010] A pressure-applying structure is used to apply pressure to the bottom surface of the blocking portion.

[0011] As a further solution of the present invention: the pressure structure includes a fixed seat and a movable column, a pressure regulating chamber is opened in the fixed seat, a piston at one end of the movable column is set in the pressure regulating chamber, and the other end is fixedly connected to the blocking part.

[0012] As a further solution of the present invention: a pressure gauge is provided in the pressure regulating chamber, and the pressure regulating chamber is communicated with the pressure regulating channel.

[0013] As a further solution of the present invention: the top surface of the blocking portion is arc-shaped.

[0014] As a further solution of the present invention: an elastic air membrane is provided on the top surface of the sealing portion, a rigid support plate is fixedly provided on a side of the elastic air membrane away from the pressure relief channel, at least one pressure relief notch is provided on the rigid support plate, and a response chamber is provided in the sealing portion.

[0015] As a further solution of the present invention: the pressure relief channel is arranged at the axial position of the machine head, and a spiral channel is provided at the outlet end of the air inlet channel. The spiral channel is bent, and a plurality of the spiral channels are evenly arranged around the pressure relief channel.

[0016] As a further solution of the present invention: each spiral channel is connected to a corresponding air inlet channel, and the other end of the air inlet channel is connected to the first annular cavity.

[0017] As a further solution of the present invention: a second annular cavity is further provided between the first annular cavity and the gas source, and the size of the second annular cavity is smaller than that of the first annular cavity.

[0018] As a further solution of the present invention: a pressure sensor is provided on the head, and the pressure sensor is connected to the processor.

[0019] The plastic film processing equipment for improving the film yield according to the present invention has at least one of the following technical effects:

[0020] The pressure relief channel and sealing portion are provided to achieve automatic pressure relief when the pressure reaches a certain level. While effectively ensuring pressure stability, the air supply rate can be increased. After the starting end of the plastic film is closed, the specified pressure value can be quickly reached and maintained stable, reducing the amount of plastic film that does not meet the standards at the starting end and reducing the waste of raw materials. At the same time, the inflation capacity of the plastic film can be increased to ensure the tensile mechanical properties of the plastic film.

[0021] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which:

[0023] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0024] Figure 2 is a structural diagram of another embodiment of the present invention;

[0025] Figure 3 This invention Figure 1 A schematic diagram of the partially enlarged structure at point A in the middle;

[0026] Figure 4 This is a schematic structural diagram of the elastic air film connection of the present invention;

[0027] Figure 5 It is a structural schematic diagram of the rigid support plate of the present invention;

[0028] Figure 6 Schematic diagram of the connection structure of the spiral channel of the present invention;

[0029] Figure 7 It is a schematic structural diagram of the spiral channel of the present invention when viewed from above.

[0030] In the figure: 1. Head; 2. Air inlet channel; 3. Pressure relief channel; 4. Intermediate chamber; 5. Sealing part; 6. Pressure-applying structure; 7. Fixed seat; 8. Movable column; 9. Pressure-regulating channel; 10. Elastic air film; 11. Rigid support plate; 12. Pressure relief notch; 13. Spiral channel; 14. First annular cavity; 15. Second annular cavity. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing 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, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0033] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0034] In the prior art, during the inflation of plastic film, since inflation requires continuous air supply, the pressure controllability of the inflation process is low, and pressure fluctuations can lead to fluctuations in the processing quality of the plastic film. In order to improve the controllability of pressure and reduce pressure fluctuations, only a slow air supply method can be used. This results in a long time required to increase the pressure, inflate, and regulate the pressure during the initial extrusion of the film, which in turn leads to the problem that the film raw materials at the starting end cannot meet the quality requirements, resulting in a large amount of waste of raw materials. In the present application, a pressure relief channel and a blocking portion are provided to achieve automatic pressure relief after the pressure value reaches a certain level. On the basis of effectively ensuring pressure stability, the air supply rate can be increased. After the starting end of the plastic film is closed and sealed, the specified pressure value can be quickly reached and maintained stable, reducing the amount of non-standard plastic film at the starting end and reducing the waste of raw materials. At the same time, the inflation capacity of the plastic film can be increased to ensure the mechanical properties of the plastic film under stretching.

[0035] See also Figure 1-7 As shown, the present invention is a plastic film processing device for improving film yield, comprising a die head 1, a sealing portion 5, and a pressure-applying structure 6. The die head 1 is provided with an air inlet channel 2 and a pressure relief channel 3. The air inlet channel 2 is connected to an air source, and the pressure relief channel 3 is connected to an intermediate chamber 4, which is larger than the pressure relief channel 3. The sealing portion 5 is located within the intermediate chamber 4, with its top surface abutting the outlet of the pressure relief channel 3. The pressure-applying structure 6 is used to apply pressure to the bottom surface of the sealing portion 5.

[0036] See also Figure 1-2In one embodiment of the present invention, the head 1 is used to discharge the molten plastic material for subsequent blowing, etc. A cooling air ring structure is provided on the outside of the head 1 to cool the molten plastic, so that the plastic changes from a viscous flow state to a highly elastic state. An air inlet channel 2 and a pressure relief channel 3 are provided in the head 1. The air inlet channel 2 is connected to the air source and is used to introduce gas into the expanded plastic for pressure-boosting and blowing. The air source can be a compressed air storage device or an air compressor. The pressure relief channel 3 is connected to the intermediate chamber 4, and the size of the intermediate chamber 4 is larger than the size of the pressure relief channel 3; that is, a larger intermediate chamber 4 is also provided in the head 1, and the two ends of the intermediate chamber 4 are respectively two sections of pressure relief channels 3, one section is in the same direction as the top of the head 1, and the other section leads to the outside.

[0037] See also Figure 1-2 In one embodiment of the present invention, the blocking portion 5 is located in the intermediate chamber 4, and the top surface of the blocking portion 5 abuts against the outlet end of the pressure relief channel 3; the pressure-applying structure 6 is used to apply pressure to the bottom surface of the blocking portion 5. Under the action of the pressure of the pressure-applying structure 6, the blocking portion 5 abuts against the outlet end of the pressure relief channel 3, thereby completing the separation between the pressure relief channel 3 and the intermediate chamber 4. When the pressure on the top surface of the blocking portion 5 (i.e., the pressure in the pressure relief channel 3) is less than the pressure on the bottom surface of the blocking portion 5 (i.e., the pressure applied by the pressure-applying structure 6 to the bottom surface of the blocking portion 5), the blocking portion 5 will remain in a state of abutting against the pressure relief channel 3. When the pressure on the top surface of the blocking portion 5 is greater than the pressure on the bottom surface of the blocking portion 5, the blocking portion 5 will detach from the outlet end of the pressure relief channel 3 under the action of the pressure difference, so that the pressure relief channel 3 is connected to the intermediate chamber 4, completing the pressure relief action. When the pressure applied by the pressure-applying structure 6 is stable, it can ensure that the pressure of the space above the pressure relief channel 3 remains within a stable range.

[0038] See also Figure 1-3In one embodiment of the present invention, the pressure-applying structure 6 can be an elastic structure such as a compression spring, but the elastic force of the compression spring may change to a certain extent after fatigue. In this embodiment, as an example, the pressure-applying structure 6 includes a fixed seat 7 and a movable column 8. A pressure-regulating chamber is provided in the fixed seat 7. A piston at one end of the movable column 8 is set in the pressure-regulating chamber, and the other end is fixedly connected to the blocking portion 5. A certain amount of gas is filled in the pressure-regulating chamber so that a certain pressure is maintained in the pressure-regulating chamber, thereby pushing the movable column 8 and the blocking portion 5 upward to abut against the outlet end of the pressure relief channel 3, thereby achieving the effect of applying a target pressure value to the bottom surface of the blocking portion 5. When the pressure on the top surface of the blocking portion 5 is greater than the pressure on the bottom surface, the blocking portion 5 will separate from the open end of the pressure relief channel 3 to achieve a pressure relief action. Furthermore, a pressure gauge can be provided in the pressure-regulating chamber, and the pressure-regulating chamber is connected to the pressure-regulating channel 9. The pressure condition in the pressure-regulating chamber can be intuitively observed through the pressure gauge. The pressure regulating channel 9 can be provided to change the pressure value in the pressure regulating chamber, thereby changing the target pressure value applied to the bottom surface of the blocking portion 5. This can be achieved by connecting the pressure regulating channel 9 to another gas source, and a control valve can be provided on the pressure regulating channel 9 to control on / off.

[0039] See also Figure 4-5 In one embodiment of the present invention, the top surface of the sealing portion 5 can be set to an arc shape to ensure the sealing effect on the pressure relief channel 3, and at the same time improve the smoothness of the pressure relief after the air pressure in the pressure relief channel 3 on the top surface of the sealing portion 5 rises to a preset value. An elastic air membrane 10 is provided on the top surface of the sealing portion 5, and a rigid support plate 11 is fixedly provided on the side of the elastic air membrane 10 away from the pressure relief channel 3. The rigid support plate 11 is provided with at least one pressure relief notch 12, and a response chamber is provided in the sealing portion 5. A certain amount of gas can be filled in the response chamber to maintain a certain pressure, and the response chamber can also be connected to the pressure regulating chamber. Under the action of pressure, the elastic air membrane 10 is made to abut the outlet end of the pressure relief channel 3 to complete the sealing effect. The rigid support plate 11 can play a supporting role and maintain the shape of the elastic air membrane 10, which can further ensure the sealing effect. At least one pressure relief notch 12 is provided on the rigid support plate 11 at the bottom surface of the elastic air membrane 10. When the pressure on the top surface of the sealing portion 5 exceeds the pressure on the bottom surface, but the pressure difference between the two surfaces is not sufficient to cause the sealing portion 5 to detach to form a larger gap, the elastic air membrane 10 at the position of the pressure relief notch 12 will undergo a slight deformation, forming a small exhaust path, thereby ensuring the stability of the pressure in the pressure relief channel 3, improving the response ability and sensitivity of the sealing portion 5 to changes in air pressure, and reducing the fluctuation amplitude of the pressure in the pressure relief channel 3.

[0040] See also Figure 6-7In one embodiment of the present invention, the air inlet channel 2 can be set at the axial position of the head 1, and the pressure relief channel 3 can be set on the outside. The pressure relief channel 3 can also be set at the axial position of the head 1, and the air inlet channel 2 can be set on the outside in a ring-shaped distribution. In the prior art, the vertical stretching of the film and the lateral stretching of the film caused by slow ventilation are independent of each other, so that the orientation of the molecular chain is in two independent directions, but it is difficult to ensure the mechanical properties in the inclined direction. In this embodiment, the pressure relief channel 3 is set at the axial position of the head 1, and a spiral channel 13 is set at the outlet end of the air inlet channel 2. The spiral channel 13 is bent, and multiple spiral channels 13 are evenly distributed around the pressure relief channel 3. The spiral channel 13 can be in the form of a hole opened inside the head 1, or it can be set as a tubular structure. The tubular structure shown in the accompanying drawings is set outside the head 1. The spiral channel 13 is spirally arranged, that is, it is part of a spiral line, so that it can be tilted around the axis of the head 1. Multiple spiral channels 13 are distributed in a ring around the axis of the head 1. In this way, the airflow ejected from the air inlet channel 2 can take on a certain spiral form and can rise obliquely before being discharged through the pressure relief channel 3 located in the center. This can simultaneously produce horizontal and vertical effects on the external plastic, making the horizontal and vertical stretching of the plastic film show a certain correlation, so that the molecular chains are oriented accordingly, and the overall performance of the film is improved.

[0041] See also Figure 6 In one embodiment of the present invention, each spiral channel 13 is connected to a corresponding air inlet channel 2, and the other end of the air inlet channel 2 is connected to the first annular cavity 14. By setting the first annular cavity 14 for transition, the airflow ejected from different spiral channels 13 is relatively even, ensuring the balance of force on the plastic film at different positions. A second annular cavity 15 is also provided between the first annular cavity 14 and the air source, and the size of the second annular cavity 15 is smaller than the size of the first annular cavity 14. That is, the size of the longitudinal section of the first annular cavity 14 is larger than the size of the longitudinal section of the first annular cavity 14. The first annular cavity 14 and the second annular cavity 15 are connected by a plurality of connecting holes evenly distributed around the axis of the machine head 1, and the size of the connecting holes is smaller than the cross-sectional size of the second annular cavity 15. In this way, the effect of small hole throttling can be formed. Commonly used gas sources are mostly air compressor equipment, which may cause fluctuations in gas supply pressure due to voltage changes, power fluctuations or other factors. If gas is directly supplied to the air inlet channel 2 through the gas source, the fluctuation of the gas source will directly affect the stability of the pressure inside the bubble of the plastic film, and thus have a negative impact on the quality of the plastic film. In this embodiment, a smaller second annular cavity 15 and a connecting hole are provided to form a small hole throttling effect, which appropriately reduces the energy of the airflow provided by the gas source, and at the same time suppresses fluctuations in the airflow, avoids causing fluctuations in the pressure inside the bubble of the plastic film, and ensures the quality of the plastic film.

[0042] See also Figure 6 In one embodiment of the present invention, the die head 1 is equipped with a pressure sensor connected to a processor. The pressure sensor is used to periodically collect pressure information within the plastic film bubble formed after inflation and transmit it to the processor. The processor compares the pressure information with a preset pressure value or pressure range to determine whether it meets the desired value, thereby effectively monitoring production pressure. The processor can process the pressure information to form a pressure fluctuation curve, allowing for more intuitive observation of pressure changes. Furthermore, the processor can process the pressure information collected by the pressure sensor. A preset pressure value A can be set within the processor. This preset pressure value A is the preferred process value for ensuring plastic film processing quality. A preset pressure differential value Q can also be set. This preset pressure differential value Q is the maximum acceptable difference between the pressure that ensures plastic film processing quality and the preferred preset pressure differential value. That is, the plastic film processing quality can be guaranteed within the range of pressure values ​​A±Q. The pressure information collected at each time is Xn, where n = 1, 2, 3, 4... (i.e., n is a positive integer). Then the real-time pressure difference q = |Xn-A|. When q is greater than Q, the processor sends a corresponding signal to remind the staff to take corresponding measures. Alternatively, a fluctuation preset value can be set, and the real-time fluctuation pressure difference x = |Xn-Xn-1|. When the real-time fluctuation pressure difference x is greater than the fluctuation preset value, a corresponding alarm signal is issued. At the same time as the processor sends the corresponding signal, the corresponding area of ​​the plastic film can be marked. The marking method can be done by manually marking. The processor can also set the plastic film at the initial processing or at a certain position as a reference value. Since the speed of the plastic film winding is fixed, the marked area can be located by time and reference value. In the existing technology, there is a lack of effective monitoring of pressure fluctuations. When defects in the plastic film appear, they cannot be discovered in time, which may eventually lead to the flow of inferior or defective products to customers, thereby causing negative effects. In this embodiment, a processor and a pressure sensor are provided to monitor the corresponding pressure conditions in a timely manner and send a corresponding signal to remind the staff when the pressure is abnormal. Furthermore, the plastic film can be marked so that staff can subsequently conduct focused inspections or separate out the plastic film produced during periods of abnormal pressure to prevent inferior or defective products from entering the customer's inventory.

[0043] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A plastic film processing device for improving film yield, characterized in that: include: A machine head (1), wherein an air inlet channel (2) and a pressure relief channel (3) are provided in the machine head (1), wherein the air inlet channel (2) is connected to an air source, and the pressure relief channel (3) is connected to an intermediate chamber (4), and the size of the intermediate chamber (4) is larger than the size of the pressure relief channel (3); A blocking portion (5), the blocking portion (5) being located in the intermediate chamber (4), and the top surface of the blocking portion (5) abutting against the outlet end of the pressure relief channel (3); A pressure-applying structure (6), wherein the pressure-applying structure (6) is used to apply pressure to the bottom surface of the blocking portion (5): The pressure relief channel (3) is arranged at the axial position of the machine head (1), and a spiral channel (13) is provided at the outlet end of the air inlet channel (2). The spiral channel (13) is bent, and a plurality of the spiral channels (13) are evenly arranged around the pressure relief channel (3).

2. A plastic film processing device for improving film yield according to claim 1, characterized in that: The pressure structure (6) comprises a fixed seat (7) and a movable column (8), wherein a pressure regulating chamber is provided in the fixed seat (7), a piston at one end of the movable column (8) is arranged in the pressure regulating chamber, and the other end is fixedly connected to the blocking portion (5).

3. The plastic film processing equipment for improving film yield according to claim 2, characterized in that: A pressure gauge is provided in the pressure regulating chamber, and the pressure regulating chamber is communicated with the pressure regulating channel (9).

4. The plastic film processing equipment for improving film yield according to claim 3, characterized in that: The top surface of the blocking portion (5) is arc-shaped.

5. The plastic film processing equipment for improving film yield according to claim 4, characterized in that: An elastic air membrane (10) is provided on the top surface of the blocking portion (5), a rigid support plate (11) is fixedly provided on a side of the elastic air membrane (10) away from the pressure relief channel (3), at least one pressure relief notch (12) is provided on the rigid support plate (11), and a response chamber is provided in the blocking portion (5).

6. The plastic film processing equipment for improving film yield according to claim 1, characterized in that: Each spiral channel (13) is in communication with a corresponding air inlet channel (2), and the other end of the air inlet channel (2) is in communication with the first annular cavity (14).

7. The plastic film processing equipment for improving film yield according to claim 6, characterized in that: A second annular cavity (15) is further provided between the first annular cavity (14) and the gas source, and the size of the second annular cavity (15) is smaller than the size of the first annular cavity (14).

8. The plastic film processing equipment for improving film yield according to claim 7, characterized in that: A pressure sensor is provided on the machine head (1), and the pressure sensor is connected to the processor.

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