High-efficiency heating system for PET bottle blow molding

Abstract

The utility model provides a kind of PET bottle blow molding's high-efficiency heating system, including strip-shaped conveying track, its upper end has the heating tunnel of length direction, two ends opening, and there are multiple inverted U-shaped heating pipes in tunnel. The upper end of track is equipped with strip-shaped conveying frame, track forms conveying slide between two conveying frames, there is vertical conveying belt in conveying frame, and there is driving motor on conveying frame. It further includes several conveying blocks that can slide on conveying slide, conveying block slides with conveying belt, its upper end is rotatably connected with turntable, there is inserting shaft on the middle part of turntable, and there is rotating shaft, rotating shaft penetrates conveying block rotating hole, and there is transmission gear on lower end. The lower end of track conveying slide has transmission slide, and one side has transmission rack. The utility model improves heating uniformity by rotating bottle blank, and overcomes the problem of uneven heat field.

Description

Technical Field

[0001] This utility model belongs to the field of bottle manufacturing technology and relates to a high-efficiency heating system for blow molding of PET bottles. Background Technology

[0002] In the manufacturing process of polyethylene terephthalate (PET) hollow containers, blow molding is a crucial step in achieving the final shape of the bottle. This process typically employs a two-step method: first, a tubular preform is produced through injection molding; then, the preform is fed into a blow molding station, where it is heated to a specific thermoplastic window above its glass transition temperature (approximately 70–120°C) but below its melting point. High-pressure gas is then used to expand and adhere it to the inner wall of the mold, thus obtaining the finished bottle of the desired shape and size. During this process, the uniform heating of the preform directly determines the material's ductility, wall thickness distribution, transparency, and overall mechanical properties, making it a core factor affecting product quality and production efficiency.

[0003] To achieve the aforementioned thermoplastic deformation, existing technologies generally employ infrared radiation heating systems to preheat the preform. A typical structure includes multiple arrays of infrared lamps arranged along the conveyor path, working with reflectors to focus heat radiation onto the surface of the moving preform. However, due to equipment layout and space constraints, current mainstream heating systems typically apply heat only from the left and right sides of the preform (i.e., horizontally), while the front, back, and bottom areas receive significantly insufficient heat due to obstruction or limited radiation angle. This unidirectional or bidirectional heating method easily leads to uneven circumferential and axial temperature distribution of the preform—for example, the light-facing side may overheat and soften or even partially melt, while the shaded side remains at a lower temperature and lacks ductility. This results in problems such as uneven bottle wall thickness during blowing, poor bottom forming, shoulder cracking, and even bottle bursting due to stress concentration, severely impacting yield and product consistency. Utility Model Content

[0004] The purpose of this invention is to provide a high-efficiency heating system for PET bottle blow molding. By rotating the preform, the uniformity of heating is improved, overcoming the problem of uneven thermal field caused by unidirectional heating, thereby improving the quality stability and process flexibility of PET bottle blow molding.

[0005] To solve the above-mentioned technical problems, this utility model provides a high-efficiency heating system for PET bottle blow molding, including a strip conveyor track. The upper end of the strip conveyor track is provided with a heating tunnel that is open at both ends and runs along its length. Multiple inverted U-shaped heating tubes are provided in the heating tunnel. The two long sides of the upper end of the strip conveyor track are provided with strip conveyor frames that run along its length. The strip conveyor track forms a conveyor slide between the two strip conveyor frames. Each strip conveyor frame has a vertical conveyor belt that runs along its length and is movably installed in it. Each strip conveyor frame is equipped with a drive motor for driving the corresponding vertical conveyor belt.

[0006] It also includes several sliding conveyor blocks that can slide within the conveyor slide. The sliding conveyor blocks slide along the conveyor slide with the vertical conveyor belt. Each sliding conveyor block has a turntable rotatably connected to its upper end. Each turntable has an insert shaft installed upward in its middle and a rotating hole that passes through each sliding conveyor block downward. Each turntable has a rotating shaft installed downward in its middle and rotatably connected to the corresponding rotating hole. Each rotating shaft has a transmission gear installed at its lower end that extends out of the corresponding rotating hole. The strip conveyor track has a transmission slide that cooperates with the transmission gear at the lower end of the conveyor slide. A transmission rack that cooperates with the transmission gear is installed on one side of the transmission slide.

[0007] By adopting the above technical solution, the two ends of the strip conveyor track are respectively connected to the feeding mechanism and the blow molding mechanism. The sliding conveyor block circulates between the feeding mechanism, the heating system, and the blow molding mechanism. When it is necessary to heat the PET preform, the preform is first inserted with its opening facing down into the insertion shaft of the turntable at the upper end of the sliding conveyor block. Then, the drive motor is started, and the drive motor drives the vertical conveyor belt to move. When the vertical conveyor belt moves, the sliding conveyor block slides along the conveyor track with the vertical conveyor belt. During the sliding process of the sliding conveyor block, the transmission gear at the lower end of the turntable's shaft meshes with the transmission rack in the transmission track. As the sliding conveyor block moves, the transmission gear rolls on the transmission rack, thereby driving the turntable to rotate. The rotation of the turntable causes the preform inserted on the insertion shaft to rotate in the heating tunnel. Meanwhile, the inverted U-shaped heating tubes inside the heating tunnel generate heat to uniformly heat the rotating preform, ensuring that the preform is heated evenly within a specific thermoplastic window above the glass transition temperature and below the melting point. This improves the uneven thermal field caused by the previous single heating direction, enhancing the quality stability and process flexibility of PET bottle blow molding.

[0008] The present invention is further provided that the inner wall of the strip conveying track is provided with heat source reflective aluminum foil.

[0009] The present invention is further configured such that the heat source reflective aluminum foil is recessed inward to form multiple arc-shaped reflective grooves that correspond one-to-one with the heating tube.

[0010] The present invention is further configured such that neither end of the heating tunnel extends to the end of the strip conveying track.

[0011] The present invention is further configured such that the inner wall of each vertical conveyor belt is provided with a number of transmission teeth distributed along its length direction, each strip conveyor frame is rotatably connected to both ends of the corresponding vertical conveyor belt with drive gears that mesh with the transmission teeth, and the power output shaft of each drive motor is connected to one end of one of the drive gears.

[0012] The present invention is further configured such that each vertical conveyor belt has a number of conveying teeth distributed along its length on its outer wall, and each sliding conveyor block has meshing racks on both sides that mesh with the corresponding conveying teeth.

[0013] The present invention is further configured such that each sliding conveyor block has a downward-facing rotating groove at its upper end that rotates in conjunction with the corresponding turntable.

[0014] Compared with existing technologies, this invention effectively solves the problem of uneven heating of the preform caused by the unidirectional heating in traditional heating methods by setting up a mechanism that allows the preform to rotate during the heating process. Under the action of the inverted U-shaped heating tube, the rotating preform can receive heat from all directions, making the circumferential and axial temperature distribution of the preform more uniform. This avoids problems such as uneven bottle wall thickness, poor bottom forming, bottle shoulder cracking, and bottle bursting caused by local overheating or overcooling during the blowing process. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0016] Figure 2 Used to demonstrate the structure of conveyor tracks and transmission tracks;

[0017] Figure 3 This is a partial sectional view used to show the internal structure of the strip conveyor frame;

[0018] Figure 4 Used to demonstrate the connection between the sliding conveyor block and the rotating shaft.

[0019] The components include: 1. Strip conveyor track; 2. Heating tunnel; 3. Heating pipe; 4. Heat source reflective aluminum foil; 5. Strip conveyor frame; 6. Conveying slide; 7. Vertical conveyor belt; 8. Drive motor; 9. Transmission gear; 10. Drive gear; 11. Sliding conveyor block; 12. Conveying gear; 13. Meshing rack; 14. Turntable; 15. Rotating groove; 16. Insert shaft; 17. Rotating hole; 18. Rotating shaft; 19. Transmission gear; 20. Transmission slide; 21. Transmission rack. Detailed Implementation

[0020] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a more detailed explanation of the efficient heating system for PET bottle blow molding proposed in this utility model. The advantages and features of this utility model will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, used only to facilitate and clarify the illustration of the embodiments of this utility model. The same or similar reference numerals in the drawings represent the same or similar parts.

[0021] Example, refer to Figure 1-4 A high-efficiency heating system for PET bottle blow molding includes a strip conveyor track 1. A heating tunnel 2 is provided at the upper end of the strip conveyor track 1, which is open at both ends and runs along its length. Neither end of the heating tunnel 2 extends to the end of the strip conveyor track 1. Multiple inverted U-shaped heating tubes 3 are provided inside the heating tunnel 2. A heat source reflective aluminum foil 4 is provided on the inner wall of the strip conveyor track 1. The heat source reflective aluminum foil 4 is recessed inward to form multiple arc-shaped reflective grooves that match the heating tubes 3 one by one. The infrared rays generated by the heating tubes 3 are reflected onto the bottle preform through the heat source reflective aluminum foil 4, resulting in higher heating efficiency.

[0022] A strip conveyor frame 5 is provided on each of the two long sides of the upper end of the strip conveyor track 1, and a conveyor slide 6 is formed between the two strip conveyor frames 5. A vertical conveyor belt 7 is movably installed in each strip conveyor frame 5, and a drive motor 8 is installed on each strip conveyor frame 5 to drive the corresponding vertical conveyor belt 7. Several transmission teeth 9 are provided on the inner wall of each vertical conveyor belt 7, and a drive gear 10 that meshes with the transmission teeth 9 is rotatably connected to both ends of each strip conveyor frame 5 in the corresponding vertical conveyor belt 7. The power output shaft of each drive motor 8 is connected to one end of one of the drive gears 10.

[0023] It also includes several sliding conveyor blocks 11 that can slide within the conveyor chute 6. Each vertical conveyor belt 7 has several conveyor teeth 12 distributed along its length on its outer wall. Each sliding conveyor block 11 has meshing racks 13 on both sides that mesh with the corresponding conveyor teeth 12, allowing the sliding conveyor block 11 to slide along the conveyor chute 6 with the vertical conveyor belt 7. A turntable 14 is rotatably connected to the upper end of each sliding conveyor block 11. A rotating groove 15 is opened downwards at the upper end of each sliding conveyor block 11 to cooperate with the corresponding turntable 14. A shaft 16 is installed upwards in the middle of each turntable 14 for inserting the bottle preform with its opening facing downwards into the shaft 16. A rotating hole 17 is opened downwards through each sliding conveyor block 11. A rotating shaft 18 is installed downwards in the middle of each turntable 14 and rotatably connected to the corresponding rotating hole 17. Each rotating shaft 18... Each of the lower ends of the 8 extends out of the corresponding rotating hole 17 and is provided with a transmission gear 19. The strip conveying track 1 has a transmission slide 20 at the lower end of the conveying slide 6 that cooperates with the transmission gear 19. A transmission rack 21 that cooperates with the transmission gear 19 is provided on one side of the transmission slide 20. When the sliding conveying block 11 slides along the conveying slide 6, the transmission rack 21 in the transmission slide 20 meshes with the transmission gear 19 to drive the turntable 14 to rotate, and finally drive the bottle preform to rotate and heat in the heating tunnel 2.

[0024] Working principle: The two ends of the strip conveyor track 1 are respectively connected to the feeding mechanism and the blow molding mechanism. The sliding conveyor block 11 circulates between the feeding mechanism, the heating system, and the blow molding mechanism. When it is necessary to heat the PET preform, the preform is first inserted with the opening facing down into the insertion shaft 16 of the turntable 14 at the upper end of the sliding conveyor block 11. Then, the drive motor 8 is started, and the drive motor 8 drives the drive gear 10 to rotate. Since the drive gear 10 meshes with the transmission teeth 9 on the inner wall of the vertical conveyor belt 7, it drives the vertical conveyor belt 7 to move. When the vertical conveyor belt 7 moves, the conveying teeth 12 on its outer wall cooperate with the meshing racks 13 on both sides of the sliding conveyor block 11, so that the sliding conveyor block 11 slides along the conveyor slide 6 with the vertical conveyor belt 7. During the sliding of the sliding conveyor block 11, the transmission gear 19 at the lower end of the rotating shaft 18 of the turntable 14 meshes with the transmission rack 21 in the transmission slide 20. As the sliding conveyor block 11 moves, the transmission gear 19 rolls on the transmission rack 21, thereby driving the turntable 14 to rotate. The rotation of the turntable 14 causes the preform inserted on the insertion shaft 16 to rotate in the heating tunnel 2. At the same time, the inverted U-shaped heating tube 3 in the heating tunnel 2 emits heat, and the heat source reflective aluminum foil 4 on the inner wall of the strip conveyor track 1 reflects the infrared rays generated by the heating tube 3 onto the preform, uniformly heating the rotating preform. This ensures that the preform is heated evenly within a specific thermoplastic window above the glass transition temperature and below the melting point, improving the uneven thermal field caused by the previous single heating direction and enhancing the quality stability and process flexibility of PET bottle blow molding.

[0025] It should also be noted that all terms such as "set up" and similar descriptive words in this application (especially the specification) indicate that two structures have or exist a connection relationship. However, the specific means by which the two are connected are not limited in detail, and are usually conventional connection methods. That is, the means should be understood as prior art and do not need to be elaborated. For example, "m is set up with n" only indicates that structure m has structure n, and whether the two are connected by welding, riveting, adhesive, or integral molding is within the scope of protection of this application. Similarly, "x is rotatably set up with y" only indicates that y and x can rotate relative to each other, and whether the two are connected by a bearing, or whether y directly passes through x and is rotatably connected to x, or other feasible methods, are all within the scope of protection of this application.

[0026] The above description is only a description of the preferred embodiment of the present utility model and is not intended to limit the scope of the present utility model in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A high-efficiency heating system for PET bottle blow molding, comprising a strip conveyor track (1), characterized in that, The upper end of the strip conveying track (1) is provided with a heating tunnel (2) that is open at both ends and runs along its length. The heating tunnel (2) is provided with multiple inverted U-shaped heating pipes (3). The two long sides of the upper end of the strip conveying track (1) are provided with strip conveying frames (5) that run along its length. The strip conveying track (1) forms a conveying slide (6) between the two strip conveying frames (5). Each strip conveying frame (5) is provided with a vertical conveyor belt (7) that runs along its length. Each strip conveying frame (5) is equipped with a drive motor (8) for driving the corresponding vertical conveyor belt (7) to move. It also includes several sliding conveyor blocks (11) that can slide within the conveyor slide (6). The sliding conveyor blocks (11) slide along the conveyor slide (6) with the vertical conveyor belt (7). Each sliding conveyor block (11) is rotatably connected to a turntable (14) at its upper end. Each turntable (14) has an insert shaft (16) installed upward in its middle. Each sliding conveyor block (11) has a rotating hole (17) that extends downward through it. Each turntable (14) has a rotating shaft (18) that is rotatably connected to the corresponding rotating hole (17) installed downward in its middle. Each rotating shaft (18) has a transmission gear (19) installed at its lower end that extends out of the corresponding rotating hole (17). The strip conveyor track (1) has a transmission slide (20) that cooperates with the transmission gear (19) at the lower end of the conveyor slide (6). A transmission rack (21) that cooperates with the transmission gear (19) is installed on one side of the transmission slide (20).

2. The high-efficiency heating system for PET bottle blow molding according to claim 1, characterized in that, The inner wall of the strip conveyor track (1) is provided with heat source reflective aluminum foil (4).

3. The high-efficiency heating system for PET bottle blow molding according to claim 2, characterized in that, The heat source reflective aluminum foil (4) is recessed inward to form multiple arc-shaped reflective grooves that correspond one-to-one with the heating tube (3).

4. The high-efficiency heating system for PET bottle blow molding according to claim 1, characterized in that, Neither end of the heating tunnel (2) extends to the end of the strip conveyor track (1).

5. The high-efficiency heating system for PET bottle blow molding according to claim 1, characterized in that, Each vertical conveyor belt (7) has several transmission teeth (9) distributed along its length on its inner wall. Each strip conveyor frame (5) has a drive gear (10) that meshes with the transmission teeth (9) at both ends of the corresponding vertical conveyor belt (7). The power output shaft of each drive motor (8) is connected to one end of one of the drive gears (10).

6. The high-efficiency heating system for PET bottle blow molding according to claim 1, characterized in that, Each vertical conveyor belt (7) has several conveying teeth (12) distributed along its length on its outer wall, and each sliding conveyor block (11) has meshing racks (13) on both sides that mesh with the corresponding conveying teeth (12).

7. The high-efficiency heating system for PET bottle blow molding according to claim 1, characterized in that, Each sliding conveyor block (11) has a downward-facing rotating groove (15) at its upper end that rotates in conjunction with the corresponding turntable (14).

Images