PVA circulating film double-temperature heat sealing device and method

Abstract

The invention belongs to the technical field of heat sealing devices, and discloses a PVA circulating film double-temperature heat sealing device which comprises a base provided with a central control system, a protective shell is installed at the top of the base, a guide rod and a lower sealing base are installed on the upper side of the base, and a first telescopic cylinder and a second telescopic cylinder are installed at the top in the protective shell. The output end of the first telescopic cylinder is connected with an upper sealing base, sealing head mechanisms are installed in the upper sealing base and the lower sealing base correspondingly, and a fixing base is installed in the installation groove. A through notch is formed in the upper sealing seat, a spring is installed between each moving block and the side wall of the corresponding moving notch, and a rotating roller is rotationally installed between the moving blocks on the two sides; the heat pipe is connected with a heat supply mechanism, the cold pipe is connected with a cold supply mechanism, and the heat supply mechanism and the cold supply mechanism are connected with an air supply mechanism together. The double-temperature heat sealing method for the PVA circulating film comprises the following use steps: S1, setting parameters; s2, feeding is started; and S3, heat sealing is completed.

Description

Technical Field

[0001] The invention belongs to the technical field of heat sealing devices, and in particular relates to a PVA circulating film dual-temperature heat sealing device and method. Background Art

[0002] PVA recycling film is a kind of biodegradable green packaging material with superior performance, which has a wide range of applications and unique characteristics. PVA recycling film is suitable for various plastic films, composite films, aluminum foils, sheets and other packaging materials. It is also suitable for the determination of oxygen permeability and oxygen permeability coefficient of various packaging containers such as packaging boxes, bottles and bags. PVA recycling film has excellent waterproof performance and can effectively block water penetration; at the same time, it has good solubility and repeatability, which is convenient for product unpacking and resealing to achieve recycling; in addition, PVA recycling film also has high durability, can maintain waterproof effect for a long time, and extend the shelf life of products. PVA material is biodegradable and recyclable, environmentally friendly and in line with the requirements of sustainable development.

[0003] The applicant proposed that the current heat sealing device has the following problems:

[0004] The temperature of the sealing head can only be increased but not decreased, which leads to the problem of melting of the PVA circulating film at the subsequent heat sealing position when the sealing head is operated at a high frequency, which in turn leads to problems with the quality of the heat seal. In addition, the quality of the manually leveled circulating film before heat sealing varies from person to person, which also leads to poor consistency in the quality of the heat-sealed circulating film.

[0005] Therefore, how to optimize and improve is a problem that needs to be considered at present. Summary of the invention

[0006] In view of the problems raised by the above background technology, the purpose of the present invention is to provide a PVA circulating film dual-temperature heat sealing device and method.

[0007] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0008] A PVA circulating film dual-temperature heat sealing device, comprising a base with a central control system installed, a protective shell installed on the top of the base, a guide rod and a lower sealing seat installed on the upper side of the base, a first telescopic cylinder and a second telescopic cylinder installed on the top of the protective shell, an upper sealing seat connected to the output end of the first telescopic cylinder, the upper sealing seat slidably installed on the guide rod, the upper sealing seat and the lower sealing seat are opposite to each other, and a sealing head mechanism is installed inside the upper sealing seat and the lower sealing seat;

[0009] The lower sealing seat is provided with a mounting groove, a fixing seat is installed in the mounting groove, and the sealing head mechanism is installed in the mounting groove;

[0010] The upper sealing seat is provided with a through slot, and the upper sealing seat is provided with a limiting slot on the side of the through slot, a lower pressure block is slidably installed in the through slot, the output end of the second telescopic cylinder is connected to the middle position of the lower pressure block, the head sealing mechanism is installed in the lower pressure block and the limiting slot, the upper sealing seat is provided with a rolling slot at the lower end of the through slot, two groups of movable slots are provided on both sides of the rolling slot, and movable blocks are slidably installed in the two groups of movable slots, springs are installed between the movable blocks and the side walls of the movable slot, and rollers are rotatably installed between the movable blocks on both sides, and the lower end of the lower pressure block is located in the gap between the two rollers;

[0011] The sealing head mechanism comprises a thermal conductive sheet, the thermal conductive sheet is integrally connected with a heat conductive sheet and a cold conductive sheet, the end of the heat conductive sheet is connected with a heat pipe, and the end of the cold conductive sheet is connected with a cold pipe;

[0012] The input and output ends of the heat pipe are connected to a heating mechanism, and the heating mechanism provides heat to the upper and lower end end end end end ends of the cold pipe, and the cooling mechanism provides cooling to the upper and lower end end end end ends of the cold pipe, and the heating mechanism and the cooling mechanism are connected to an air supply mechanism;

[0013] A dual-temperature heat sealing method for a PVA circulating film comprises the following steps:

[0014] S1, parameter setting;

[0015] S2, loading starts;

[0016] S3, heat sealing is completed.

[0017] It is further defined that the heating mechanism includes a heating box equipped with a pump, the output end of the pump is connected to a first heating pipe, the output end of the first heating pipe is connected to the input end of the heat pipe located on the upper side, the output end of the heat pipe located on the upper side is connected to a second heating pipe, the output end of the second heating pipe is connected to a third heating pipe, the output end of the third heating pipe is connected to the input end of the heat pipe located on the lower side, the output end of the heat pipe located on the lower side is connected to a fourth heating pipe, and the output end of the fourth heating pipe is located in the heating box. Such a design realizes circulating heating.

[0018] It is further defined that the cooling mechanism includes a cooling box equipped with a pump, the output end of the pump is connected to a first cooling supply pipe, the output end of the first cooling supply pipe is connected to the input end of the cold pipe located on the upper side, the output end of the cold pipe located on the upper side is connected to a second cooling supply pipe, the output end of the second cooling supply pipe is connected to a third cooling supply pipe, the output end of the third cooling supply pipe is connected to the input end of the cold pipe located on the lower side, the output end of the cold pipe located on the lower side is connected to a fourth cooling supply pipe, and the output end of the fourth cooling supply pipe is located in the cooling box. Such a design realizes circulating refrigeration.

[0019] It is further defined that the air supply mechanism includes an air inlet pipe connected to the output end of the compressor, the output end of the air inlet pipe is connected to a three-way air distribution pipe, one output end of the three-way air distribution pipe is connected to the tube body of the third heating pipe, and the other output end of the three-way air distribution pipe is connected to the tube body of the third cooling pipe. Such a design can quickly clear the hot liquid or cold liquid in each pipe.

[0020] It is further defined that both output ends of the three-way gas distribution pipe are equipped with a one-way three-way valve, and the one-way three-way valve has two one-way outlets and one one-way inlet. Such a design ensures the correct flow direction of the gas.

[0021] It is further defined that external threads are provided on both sides of the roller from the center position to the roller. Such a design allows the circulating film to be flattened toward both sides due to friction during rotation.

[0022] It is further defined that in step S1, the parameter settings include heat sealing temperature, heat sealing time, cooling temperature, cooling time, and the stroke and downward pressure of the first telescopic cylinder and the second telescopic cylinder. Such a design ensures accurate operation.

[0023] It is further defined that in step S2, loading includes manually leveling the PVA circulating film. With such a design, manual leveling can reduce the leveling pressure of the device operation to a certain extent.

[0024] The beneficial effects of the present invention are as follows:

[0025] The present invention realizes fully automated upper and lower heat sealing of the PVA circulating film, achieving the purpose of dual-temperature heat sealing, and under the effect of the cooling mechanism, the head can also be quickly cooled down, thereby preventing the head temperature from gradually increasing under high-intensity operation, thereby preventing the heat sealing quality of the circulating film from becoming lower;

[0026] In the present invention, before heat sealing, two rollers can rotate and flatten the circulating film, thereby ensuring the heat sealing molding quality of the circulating film. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention can be further illustrated by the non-limiting examples given in the accompanying drawings;

[0028] Figure 1 A schematic diagram of a PVA circulating film dual-temperature heat sealing device according to an embodiment of the present invention Figure 1 ;

[0029] Figure 2 A schematic diagram of a PVA circulating film dual-temperature heat sealing device according to an embodiment of the present invention Figure 2 ;

[0030] Figure 3 The cross-sectional structure of a PVA circulating film dual-temperature heat sealing device according to the present invention is shown in FIG. Figure 1 ;

[0031] Figure 4 The cross-sectional structure of a PVA circulating film dual-temperature heat sealing device according to the present invention is shown in FIG. Figure 2 ;

[0032] Figure 5 It is a schematic diagram of the internal structure of a PVA circulating film dual-temperature heat sealing device embodiment of the present invention;

[0033] Figure 6 It is a schematic diagram of the roller structure of an embodiment of a PVA circulating film dual-temperature heat sealing device of the present invention;

[0034] Figure 7 for Figure 4 The enlarged structural diagram at A in the middle;

[0035] Figure 8 It is a schematic flow chart of an embodiment of a PVA circulating film double-temperature heat sealing method of the present invention;

[0036] The main component symbols are described as follows:

[0037] Base 1; protective shell 2; guide rod 3; lower sealing seat 4; first telescopic cylinder 5; second telescopic cylinder 6; upper sealing seat 7; head sealing mechanism 8; mounting groove 9; fixed seat 10; through groove 11; limit groove 12; lower pressing block 13; rolling groove 14; moving groove 15; moving block 16; spring 17; roller 18; heating mechanism 19; cooling mechanism 20; air supply mechanism 21; one-way three-way valve 22; external thread 23;

[0038] Temperature conducting plate 81; heat conducting plate 82; cold conducting plate 83; heat pipe 84; cold pipe 85;

[0039] Heating box 191; first heating pipe 192; second heating pipe 193; third heating pipe 194; fourth heating pipe 195;

[0040] Cooling box 201; first cooling pipe 202; second cooling pipe 203; third cooling pipe 204; fourth cooling pipe 205;

[0041] Air inlet pipe 211; three-way air distribution pipe 212. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0043] Embodiment 1:

[0044] like Figure 1 to Figure 4 As shown, a PVA circulating film dual-temperature heat sealing device of the present invention comprises a base 1 with a central control system installed, a protective shell 2 is installed on the top of the base 1, a guide rod 3 and a lower sealing seat 4 are installed on the upper side of the base 1, a first telescopic cylinder 5 and a second telescopic cylinder 6 are installed on the top of the protective shell 2, an output end of the first telescopic cylinder 5 is connected to an upper sealing seat 7, the upper sealing seat 7 is slidably installed on the guide rod 3, the upper sealing seat 7 and the lower sealing seat 4 are opposite to each other, and a sealing head mechanism 8 is installed inside the upper sealing seat 7 and the lower sealing seat 4;

[0045] The lower sealing seat 4 is provided with a mounting groove 9, a fixing seat 10 is installed in the mounting groove 9, and the sealing head mechanism 8 is installed in the mounting groove 9;

[0046] The upper sealing seat 7 is provided with a through slot 11, and a limiting slot 12 is provided on the side of the through slot 11. A lower pressing block 13 is slidably installed in the through slot 11. The output end of the second telescopic cylinder 6 is connected to the middle position of the lower pressing block 13. The head sealing mechanism 8 is installed in the lower pressing block 13 and the limiting slot 12. The upper sealing seat 7 is provided with a rolling slot 14 at the lower end of the through slot 11. Two groups of moving slots 15 are provided on both sides of the rolling slot 14. Moving blocks 16 are slidably installed in the two groups of moving slots 15. Springs 17 are installed between the moving blocks 16 and the side walls of the moving slots 15. Rollers 18 are rotatably installed between the moving blocks 16 on both sides. The lower end of the lower pressing block 13 is located in the gap between the two rollers 18.

[0047] The end capping mechanism 8 comprises a heat conducting plate 81, the heat conducting plate 81 is integrally connected with a heat conducting plate 82 and a cold conducting plate 83, the end of the heat conducting plate 82 is connected with a heat pipe 84, and the end of the cold conducting plate 83 is connected with a cold pipe 85;

[0048] The input and output ends of the heat pipe 84 are connected to a heating mechanism 19, which heats the upper and lower end end caps 8. The input and output ends of the cold pipe 85 are connected to a cooling mechanism 20, which cools the upper and lower end end caps 8. The heating mechanism 19 and the cooling mechanism 20 are connected to an air supply mechanism 21.

[0049] like Figure 8 As shown, a dual-temperature heat sealing method for PVA circulating film includes the following steps:

[0050] S1, parameter setting;

[0051] S2, loading starts;

[0052] S3, heat sealing is completed.

[0053] In this embodiment, when using a PVA circulating film dual-temperature heat sealing device and method, the parameters of the central control system are set on the base 1, and then the circulating film is spread out, and the circulating film is placed between the upper sealing seat 7 and the lower sealing seat 4, and the device is started, and the device starts to operate, and the circulating film is heat-sealed. After the heat sealing is completed, the circulating film can be taken out;

[0054] Specifically, when the circulating film is put into place, the first telescopic cylinder 5 starts to operate, and the upper sealing seat 7 is moved downward. During the movement, the second telescopic cylinder 6 is in a follow-up state. When the first telescopic cylinder 5 is in place, the second telescopic cylinder 6 starts to operate, driving the lower pressing block 13 downward, so that the lower pressing block 13 contacts the two rollers 18 on the lower side. The two rollers 18 are rotated under the force to flatten the circulating film to both sides. At the same time, when this action is in progress, the heating mechanism 19 starts to operate, and transfers heat to the sealing mechanism 8, so that the sealing The temperature of the contact position of the mechanism 8 rises to achieve the subsequent heat sealing purpose. After the heat sealing is completed, the air supply mechanism 21 operates to empty the heat source in the pipeline of the heating mechanism 19, and then the cooling mechanism 20 operates to transfer the cold energy to the head mechanism 8 to cool the head mechanism 8, thereby ensuring that there is no residual heat at the contact position of the head mechanism 8 during the next heat sealing. Similarly, before the next heat sealing, the air supply mechanism 21 will first empty the cold source in the cooling mechanism 20 to prevent the heat from interfering with the heating mechanism 19 and failing to reach the set temperature.

[0055] Embodiment 2:

[0056] like Figure 5As shown, in this embodiment, the heating mechanism 19 includes a heating box 191 equipped with a pump, the output end of the pump is connected to a first heating pipe 192, the output end of the first heating pipe 192 is connected to the input end of the heat pipe 84 located on the upper side, the output end of the heat pipe 84 located on the upper side is connected to a second heating pipe 193, the output end of the second heating pipe 193 is connected to a third heating pipe 194, the output end of the third heating pipe 194 is connected to the input end of the heat pipe 84 located on the lower side, the output end of the heat pipe 84 located on the lower side is connected to a fourth heating pipe 195, and the output end of the fourth heating pipe 195 is located in the heating box 191. Such a design realizes circulating heating; wherein, the heating box 191 ensures the temperature of the heat source placed inside, and the temperature control is not difficult to implement in the prior art. Now, the pump runs and supplies the heat source to the first heat supply pipe 192, and then the first heat supply pipe 192 transfers the heat source to the upper heat pipe 81, and the heat is transferred to the heat conductive sheet 82 in the form of heat transfer, and then the heat conductive sheet 82 transfers the heat to the thermal conductive sheet 81. After the thermal conductive sheet 81 reaches the temperature, it can be heat-sealed in the form of heat transfer. Under the continuous operation of the pump, the heat source flows to the second heat supply pipe 193, and then flows to the third heat supply pipe 194, and continues to transfer the heat source to the lower heat pipe 81. Similarly, the lower head mechanism 8 has the effect of heat sealing, and the heat sealing on the upper and lower sides achieves the purpose of double-temperature heat sealing. Then the heat source is transferred to the fourth heat supply pipe 195 and returned to the heating box 191, thereby realizing the circulation of the heat source and ensuring continuous operation.

[0057] Embodiment three:

[0058] like Figure 5As shown, in this embodiment, the cooling mechanism 20 includes a cooling box 201 equipped with a pump, the output end of the pump is connected to a first cooling pipe 202, the output end of the first cooling pipe 202 is connected to the input end of the cooling conduit 85 located on the upper side, the output end of the cooling conduit 85 located on the upper side is connected to a second cooling pipe 203, the output end of the second cooling pipe 203 is connected to a third cooling pipe 204, the output end of the third cooling pipe 204 is connected to the input end of the cooling conduit 85 located on the lower side, the output end of the cooling conduit 85 located on the lower side is connected to a fourth cooling pipe 205, the output end of the fourth cooling pipe 205 is located in the cooling box 201, such a design realizes circulating refrigeration; wherein, the cooling box 201 ensures the temperature of the cold source placed inside, and the temperature control is not difficult to achieve in the prior art, and then the pump runs to supply the cold source to The first cooling pipe 202, then the first cooling pipe 202 transfers the cold source to the upper cold pipe 85, the cold energy is transferred to the cold guide plate 83 in the form of cold transfer, and then the cold guide plate 83 transfers the cold energy to the thermal conductive plate 81, after the thermal conductive plate 81 has reached the temperature, it can be cooled by cold transfer to prevent the thermal conductive plate 81 from having residual heat during the next operation, which will affect the heat sealing effect next time. Under the continuous operation of the pump, the cold source flows to the second cooling pipe 203, and then flows to the third cooling pipe 204, and continues to transfer the cold source to the lower cold pipe 85. Similarly, after the lower head mechanism 8 is also cooled, the head mechanisms 8 on the upper and lower sides are cooled, and the cold source is transferred to the fourth cooling pipe 205 and returned to the cooling box 201, thereby realizing the circulation of the cold source and ensuring continuous operation.

[0059] Embodiment 4:

[0060] like Figure 5 As shown, in this embodiment, the air supply mechanism 21 includes an air inlet pipe 211 connected to the output end of the compressor, and the output end of the air inlet pipe 211 is connected to a three-way air distribution pipe 212, one output end of the three-way air distribution pipe 212 is connected to the pipe body of the third heating pipe 194, and the other output end of the three-way air distribution pipe 212 is connected to the pipe body of the third cooling pipe 204. This design can quickly clear the hot liquid or cold liquid in each pipe; wherein, after a single operation of the heating mechanism 19 and the cooling mechanism 20, the supply The air mechanism 21 will start to run, the compressor will pass air into the air pipe 211, then into the three-way air distribution pipe 212, and pass the gas into the third heating pipe 194 and the third cooling pipe 204. Under the effect of air pressure, the residual heat source or cold source in the heating mechanism 19 and the cooling mechanism 20 will be quickly emptied into the heating box 191 or the cooling box 201, so as to prevent the residual heat or cold from affecting the temperature of the thermal conductive plate 81, resulting in the temperature failing to reach the set temperature quickly.

[0061] Embodiment five:

[0062] like Figure 5As shown, in this embodiment, both output ends of the three-way gas distribution pipe 212 are equipped with a one-way three-way valve 22, and the one-way three-way valve 22 has two one-way outlets and one one-way inlet. Such a design ensures the correct flow direction of the gas. Under the effect of the three-way gas distribution pipe 212, the gas can only move toward the output end direction of the third heating pipe 194 and the third cooling pipe 204, while the heat source or the cold source cannot move toward the direction of the one-way three-way valve 22, thereby preventing interference.

[0063] Embodiment six:

[0064] like Figure 6 As shown, in the present embodiment, external threads 23 are provided on both sides of the roller 18 from the center position. With such a design, the circulating film can be flattened toward both sides due to friction when rotating, wherein the roller 18 will roll after receiving the pressure from the pressing block 13, and under the effect of this force, the moving block 16 will be forced to squeeze the spring 17 to move, and the roller 18 will roll toward both sides while rolling, thereby achieving the flattening of the circulating film, ensuring that during the subsequent heat sealing, the state of the circulating film is conducive to heat sealing and the effect after heat sealing is ensured, and under the effect of the external threads 23, the rolling of the roller 18 will roll the circulating film toward both sides, causing the circulating film to be flattened.

[0065] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A PVA circulating film dual-temperature heat sealing device, comprising a base (1) on which a central control system is installed, characterized in that: A protective shell (2) is installed on the top of the base (1), a guide rod (3) and a lower sealing seat (4) are installed on the upper side of the base (1), a first telescopic cylinder (5) and a second telescopic cylinder (6) are installed on the top of the protective shell (2), an output end of the first telescopic cylinder (5) is connected to an upper sealing seat (7), the upper sealing seat (7) is slidably installed on the guide rod (3), the upper sealing seat (7) and the lower sealing seat (4) are positioned relative to each other, and a sealing head mechanism (8) is installed inside the upper sealing seat (7) and the lower sealing seat (4); The lower sealing seat (4) is provided with a mounting groove (9), a fixing seat (10) is installed in the mounting groove (9), and the sealing head mechanism (8) is installed in the mounting groove (9); The upper sealing seat (7) is provided with a through slot (11), and a limiting groove (12) is provided on the side of the through slot (11). A lower pressing block (13) is slidably installed in the through slot (11), and the output end of the second telescopic cylinder (6) is connected to the middle section of the lower pressing block (13). The sealing head mechanism (8) is installed in the lower pressing block (13) and the limiting groove (12). The upper sealing seat (7) is at the lower end of the through slot (11). A rolling groove (14) is provided at the end, two groups of movable grooves (15) are provided on both sides of the rolling groove (14), movable blocks (16) are slidably installed in the two groups of movable grooves (15), springs (17) are installed between the movable blocks (16) and the side walls of the movable grooves (15), rollers (18) are rotatably installed between the movable blocks (16) on both sides, and the lower end of the lower pressing block (13) is located in the gap between the two rollers (18); The sealing head mechanism (8) comprises a heat conducting plate (81), the heat conducting plate (81) being integrally connected with a heat conducting plate (82) and a cold conducting plate (83), the end of the heat conducting plate (82) being connected with a heat pipe (84), and the end of the cold conducting plate (83) being connected with a cold pipe (85); The input end and the output end of the heat pipe (84) are connected to a heating mechanism (19), and the heating mechanism (19) provides heat to the upper and lower end of the sealing mechanism (8); the input end and the output end of the cold pipe (85) are connected to a cooling mechanism (20), and the cooling mechanism (20) provides cooling to the upper and lower end of the sealing mechanism (8); the heating mechanism (19) and the cooling mechanism (20) are connected to an air supply mechanism (21).

2. A PVA circulating film dual-temperature heat sealing device according to claim 1, characterized in that: The heating mechanism (19) comprises a heating box (191) equipped with a pump, the output end of the pump is connected to a first heating pipe (192), the output end of the first heating pipe (192) is connected to the input end of the heat pipe (84) located on the upper side, the output end of the heat pipe (84) located on the upper side is connected to a second heating pipe (193), the output end of the second heating pipe (193) is connected to a third heating pipe (194), the output end of the third heating pipe (194) is connected to the input end of the heat pipe (84) located on the lower side, the output end of the heat pipe (84) located on the lower side is connected to a fourth heating pipe (195), and the output end of the fourth heating pipe (195) is located in the heating box (191).

3. A PVA circulating film dual-temperature heat sealing device according to claim 2, characterized in that: The cooling mechanism (20) comprises a cooling box (201) equipped with a pump, the output end of the pump is connected to a first cooling pipe (202), the output end of the first cooling pipe (202) is connected to the input end of the cooling conduit (85) located on the upper side, the output end of the cooling conduit (85) located on the upper side is connected to a second cooling pipe (203), the output end of the second cooling pipe (203) is connected to a third cooling pipe (204), the output end of the third cooling pipe (204) is connected to the input end of the cooling conduit (85) located on the lower side, the output end of the cooling conduit (85) located on the lower side is connected to a fourth cooling pipe (205), and the output end of the fourth cooling pipe (205) is located in the cooling box (201).

4. A PVA circulating film dual-temperature heat sealing device according to claim 3, characterized in that: The air supply mechanism (21) comprises an air inlet pipe (211) connected to the output end of the compressor, the output end of the air inlet pipe (211) is connected to a three-way air distribution pipe (212), one output end of the three-way air distribution pipe (212) is connected to the pipe body of the third heating pipe (194), and the other output end of the three-way air distribution pipe (212) is connected to the pipe body of the third cooling pipe (204).

5. A PVA circulating film dual-temperature heat sealing device according to claim 4, characterized in that: A one-way three-way valve (22) is installed at both output ends of the three-way gas distribution pipe (212), and the one-way three-way valve (22) has two one-way outlets and one one-way inlet.

6. A PVA circulating film dual-temperature heat sealing device according to claim 1, characterized in that: The rotating roller (18) is provided with external threads (23) on both sides from the center position.

7. A PVA circulating film double-temperature heat sealing method, comprising a PVA circulating film double-temperature heat sealing device as claimed in claims 1 to 6, characterized in that: The usage steps include: S1, parameter setting; S2, loading starts; S3, heat sealing is completed.

8. A dual-temperature heat sealing method for PVA circulating film according to claim 7, characterized in that: In step S1, the parameter settings include heat sealing temperature, heat sealing time, cooling temperature, cooling time, and the stroke and downward pressure of the first telescopic cylinder (5) and the second telescopic cylinder (6).

9. A double-temperature heat sealing method for PVA circulating film according to claim 7, characterized in that: In step S2, loading includes manually leveling the PVA recycling film.

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