A screw extruder for PET plastic production

Abstract

This utility model discloses a screw extruder for PET plastic production, including a frame, an extrusion cylinder mounted on the frame, and an extrusion screw disposed inside the extrusion cylinder. A drive motor for rotating the extrusion screw is also mounted on the frame. An extrusion end corresponding to the output end of the extrusion screw is provided at the end of the extrusion cylinder away from the drive motor. The extrusion cylinder has a feed trough at its top, and a feeding unit is provided on the extrusion cylinder at a position corresponding to the feed trough. This screw extruder for PET plastic production, through the reciprocating unit driving the feeding hopper to reciprocate within the fixed cylinder, breaks the static accumulation of raw materials within the hopper, fundamentally avoiding bridging and material overflow, ensuring continuous and uniform entry of raw materials into the extrusion cylinder, significantly reducing extrusion pressure fluctuations caused by poor feeding, and improving the molding quality stability of PET products.

Description

Technical Field

[0001] This utility model relates to the field of screw extruder technology, and in particular to a screw extruder for PET plastic production. Background Technology

[0002] PET (polyethylene terephthalate), as a thermoplastic polyester with excellent comprehensive properties, is widely used in packaging, fiber, electronics and electrical appliances and other fields. The screw extruder is the core equipment in the PET plastic production process. Its function is to heat, melt, mix and plasticize PET raw materials (such as chips and recycled materials) and then extrude them into shapes. The stability of the extrusion process directly affects the mechanical properties and appearance quality of the final product.

[0003] Existing PET screw extruders mostly use a fixed hopper for feeding, which has revealed many problems in actual production: PET raw materials are mostly in flake or granular form and are prone to static electricity, easily forming bridging and sloshing phenomena in the hopper during feeding, leading to discontinuous feeding, fluctuations in extrusion pressure, and consequently, defects such as uneven thickness, bubbles, and even material breakage in the extruded PET products. Furthermore, traditional feeding methods rely on the raw material's own gravity, and during static feeding, the raw material tends to accumulate at a certain position at the inlet, resulting in uneven mixing and affecting subsequent plasticizing effects. Therefore, there is an urgent need for a screw extruder for PET plastic production. Utility Model Content

[0004] Therefore, it is necessary to provide a screw extruder for PET plastic production to address the above-mentioned technical problems. By setting up a reciprocating unit to drive the feeding hopper to reciprocate within the fixed cylinder, the static accumulation of raw materials in the hopper is broken, thus avoiding bridging and material slugging from the source. This ensures that the raw materials continuously and evenly enter the extrusion cylinder, significantly reducing extrusion pressure fluctuations caused by poor feeding and improving the molding quality stability of PET products.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A screw extruder for PET plastic production includes a frame, an extrusion cylinder mounted on the frame, and an extrusion screw disposed inside the extrusion cylinder. A drive motor for driving the extrusion screw to rotate is also mounted on the frame. An extrusion end corresponding to the output end of the extrusion screw is provided at the end of the extrusion cylinder away from the drive motor. The top of the extrusion cylinder has a feed trough, and a feeding unit is provided on the extrusion cylinder at a position corresponding to the feed trough. The feeding unit includes a fixed cylinder fixed above the extrusion cylinder and a feeding hopper movably disposed inside the fixed cylinder. The top wall of the inner side of the fixed cylinder is provided with a movable groove, and the bottom of the feeding hopper is located below the movable groove and is in close contact with the side wall of the fixed cylinder. The movable groove is also equipped with a reciprocating unit for driving the hopper to reciprocate within the fixed cylinder.

[0006] Furthermore, the reciprocating unit includes a guide ring fixed to the outer wall of the hopper, and the guide ring is slidably assembled inside the movable groove.

[0007] Furthermore, the side wall of the fixed cylinder has a sealing cavity, and a sliding ring is slidably disposed in the sealing cavity, with a spring fixed to the bottom of the sliding ring.

[0008] Furthermore, one end of the spring is connected to the bottom wall of the sealing cavity, and a transmission ring is connected to the top of the sliding ring, the transmission ring being connected to the guide ring.

[0009] Furthermore, the reciprocating unit also includes a servo motor, the output end of which is connected to an eccentric wheel.

[0010] Furthermore, a support frame is fixed to the bottom wall inside the fixed cylinder, and a support rod is fixed to the middle of the support frame.

[0011] Furthermore, the surface of the support rod is provided with a material distribution frame, which is located inside the hopper.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The screw extruder for PET plastic production provided by this utility model drives the feeding hopper to reciprocate within the fixed cylinder by setting a reciprocating unit, breaking the static accumulation state of the raw material in the hopper, avoiding bridging and material slugging from the source, ensuring that the raw material continuously and evenly enters the extrusion cylinder, greatly reducing the extrusion pressure fluctuation caused by poor feeding, and improving the molding quality stability of PET products.

[0013] The reciprocating motion of the hopper is achieved through the directional constraint of the guide ring and the movable groove. With the buffering and reset effect of the spring, the vibration is limited to the inside of the hopper and will not be transmitted to the extrusion barrel and screw system. This ensures smooth feeding and does not affect the stable operation of the screw, thus guaranteeing the consistency of plasticizing effect.

[0014] At the same time, during the reciprocating sliding of the hopper up and down, the relative position between it and the distribution frame can be changed, which can further promote the dispersion and flow of the material inside, so that the raw materials are evenly distributed into the feed trough and the material is avoided from being concentrated and piled up. Attached Figure Description

[0015] Figure 1 A schematic diagram of the screw extruder for PET plastic production provided by this utility model; Figure 2A top view of the screw extruder for PET plastic production provided by this utility model; Figure 3 A schematic diagram of the feeding unit structure of the screw extruder for PET plastic production provided by this utility model; Figure 4 A schematic diagram of the internal structure of the feeding unit of the screw extruder for PET plastic production provided by this utility model; Figure 5 The screw extruder for PET plastic production provided by this utility model Figure 3 Enlarged structural diagram at point A in the middle.

[0016] The markings in the diagram are explained as follows: 1. Rack; 2. Extrusion cylinder; 21. Feed trough; 3. Extrusion screw; 4. Drive motor; 5. Extrude the end; 6. Feeding unit; 61. Fixed cylinder; 62. Feeding hopper; 63. Movable trough; 610. Sealed cavity; 611. Sliding ring; 612. Spring; 613. Transmission ring; 7. Reciprocating unit; 71. Guide ring; 72. Servo motor; 73. Eccentric wheel; 8. Support frame; 81. Support rod; 82. Material distribution frame. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0018] Example 1 Please refer to Figures 1-5 A screw extruder for PET plastic production includes a frame 1, an extrusion cylinder 2 mounted on the frame 1, and an extrusion screw 3 disposed inside the extrusion cylinder 2. The frame 1 is also equipped with a drive motor 4 for driving the extrusion screw 3 to rotate. The end of the extrusion cylinder 2 away from the drive motor 4 is also provided with an extrusion end 5 corresponding to the output end of the extrusion screw 3. The extrusion cylinder 2 has a feed groove 21 at its top, and a feeding unit 6 is provided on the extrusion cylinder 2 at a position corresponding to the feed groove 21. The feeding unit 6 includes a fixed cylinder 61 fixed above the extrusion cylinder 2 and a feeding hopper 62 movably disposed inside the fixed cylinder 61. The top wall of the inner side of the fixed cylinder 61 is provided with a movable groove 63, and the bottom of the feeding hopper 62 is located below the movable groove 63 and is in close contact with the side wall of the fixed cylinder 61. The movable groove 63 is also provided with a reciprocating unit 7 for driving the hopper 62 to reciprocate within the fixed cylinder 61.

[0019] Because the screw extruder for PET plastic production of this utility model has the above structure, the feeding hopper 62 is movably assembled inside the fixed cylinder 61, and the bottom is tightly attached to the side wall of the fixed cylinder 61 to form a dynamic seal, which not only prevents the raw material from leaking from the gaps, but also retains the reciprocating movement space of the feeding hopper 62. In actual operation, the reciprocating unit 7 drives the feeding hopper 62 to slide back and forth along the movable groove 63, continuously changing the accumulation angle and stress state of the raw material in the hopper, fundamentally destroying the static balance conditions formed by bridging and material swell, ensuring that the PET raw material falls continuously and evenly into the feed trough 21, avoiding extrusion pressure fluctuations caused by interruption of feeding, significantly improving the stability of the extrusion process, and reducing the probability of defects such as uneven thickness, bubbles, and material breakage in PET products.

[0020] Example 2 The screw extruder for PET plastic production provided in Example 1 has been further optimized, specifically, as follows: Figure 3 , Figure 4 As shown, the reciprocating unit 7 includes a guide ring 71 fixed to the outer wall of the hopper 62, and the guide ring 71 is slidably assembled inside the movable groove 63.

[0021] The side wall of the fixed cylinder 61 has a sealing cavity 610, and a sliding ring 611 is slidably disposed in the sealing cavity 610. A spring 612 is fixed to the bottom of the sliding ring 611.

[0022] One end of the spring 612 is connected to the bottom wall of the sealing cavity 610, and a transmission ring 613 is connected to the top of the sliding ring 611. The transmission ring 613 is connected to the guide ring 71.

[0023] Because the screw extruder for PET plastic production of this utility model has the above structure, the cooperation between the guide ring 71 and the movable groove 63 provides precise guidance and constraint for the reciprocating motion of the feeding hopper 62, avoiding deviation and jamming during the movement of the feeding hopper 62; at the same time, the sealing cavity 610, the sliding ring 611, the spring 612 and the transmission ring 613 form a flexible transmission structure: When the hopper 62 moves downward under external force, the transmission ring 613 pushes the sliding ring 611 to compress the spring 612. The spring 612 stores elastic potential energy. When the external force is removed, the spring 612 releases the potential energy to drive the hopper 62 to reset. No additional reset mechanism is required, making the structure simple and reliable. Furthermore, this transmission path confines vibration within the feeding unit 6 and prevents it from being transmitted to the extrusion cylinder 2 and extrusion screw 3 system. While ensuring smooth feeding, it does not affect the stable operation of the extrusion screw 3, thus ensuring consistent plasticizing effect.

[0024] Example 3 The screw extruder for PET plastic production provided in Example 1 or 2 has been further optimized, such as... Figure 5 As shown, the reciprocating unit 7 also includes a servo motor 72, and the output end of the servo motor 72 is connected to an eccentric wheel 73.

[0025] Because the screw extruder for PET plastic production of this utility model has the above structure, when the servo motor 72 drives the eccentric wheel 73 to rotate, the protrusion of the eccentric wheel 73 periodically abuts against the top of the sliding ring 611, driving the feed hopper 62 to move downward. When the smooth part of the eccentric wheel 73 rotates away, the spring 612 resets and drives the feed hopper 62 to move upward, thereby forming a stable reciprocating vibration.

[0026] Example 4 The screw extruder for PET plastic production provided in Example 3 has been further optimized, such as... Figure 4 As shown, a support frame 8 is fixed to the bottom wall inside the fixed cylinder 61, and a support rod 81 is fixed to the middle of the support frame 8.

[0027] The surface of the support rod 81 is provided with a material distribution frame 82, which is located inside the hopper 62.

[0028] Because the screw extruder for PET plastic production of this utility model has the above structure, the support frame 8 and the support rod 81 provide stable support for the material distribution frame 82. The material distribution frame 82 is fixed and forms a relative displacement with the reciprocating feeding hopper 62. When the feeding hopper 62 moves up and down, the material distribution frame 82 continuously breaks up the raw materials accumulated in the hopper, disperses the clumps of PET particles, and evenly distributes the raw materials into the feed trough 21, avoiding the accumulation of materials in one position. This structure not only further enhances the anti-bridging effect, but also allows the raw materials to be initially dispersed before entering the extrusion cylinder 2, which is conducive to the uniform heat transfer in the subsequent heating section, improves the uniformity of mixing and plasticizing of the extrusion screw 3, reduces the problem of degradation of PET raw materials due to local overheating, and ultimately improves the mechanical properties and appearance quality of the finished product.

[0029] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," 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 connection that allows communication between them; 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, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0030] Obviously, the embodiments described above are only some embodiments of this utility model, not all embodiments. The accompanying drawings show preferred embodiments of this utility model, but do not limit the patent scope of this utility model. This utility model can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this utility model specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this utility model.

Claims

1. A screw extruder for PET plastic production, comprising a frame (1), an extrusion barrel (2) arranged on the frame (1), and an extrusion screw (3) arranged inside the extrusion barrel (2), a driving motor (4) for driving the extrusion screw (3) to rotate being further arranged on the frame (1), and an extrusion head (5) corresponding to the output end of the extrusion screw (3) being further arranged at the end of the extrusion barrel (2) away from the driving motor (4), characterized in that, The top of the extrusion cylinder (2) has a feed groove (21), and a feeding unit (6) is provided on the extrusion cylinder (2) at a position corresponding to the feed groove (21). The feeding unit (6) includes a fixed cylinder (61) fixed above the extrusion cylinder (2) and a feeding hopper (62) movably disposed inside the fixed cylinder (61). The top wall of the inner side of the fixed cylinder (61) is provided with a movable groove (63). The bottom of the feeding hopper (62) is located below the movable groove (63) and is in close contact with the side wall of the fixed cylinder (61). The movable groove (63) is also provided with a reciprocating unit (7) for driving the hopper (62) to reciprocate within the fixed cylinder (61).

2. The screw extruder for PET plastic production according to claim 1, characterized in that, The reciprocating unit (7) includes a guide ring (71) fixed to the outer wall of the hopper (62), and the guide ring (71) is slidably assembled inside the movable groove (63).

3. The screw extruder for PET plastic production according to claim 2, characterized in that, The side wall of the fixed cylinder (61) has a sealing cavity (610), and a sliding ring (611) is slidably provided in the sealing cavity (610). A spring (612) is fixed at the bottom of the sliding ring (611).

4. A screw extruder for PET plastic production according to claim 3, characterized in that, One end of the spring (612) is connected to the bottom wall of the sealing cavity (610), and a transmission ring (613) is connected to the top of the sliding ring (611), and the transmission ring (613) is connected to the guide ring (71).

5. A screw extruder for PET plastic production according to claim 4, characterized in that, The reciprocating unit (7) also includes a servo motor (72), the output end of which is connected to an eccentric wheel (73).

6. A screw extruder for PET plastic production according to claim 1, characterized in that, A support frame (8) is fixed to the bottom wall inside the fixed cylinder (61), and a support rod (81) is fixed to the middle of the support frame (8).

7. A screw extruder for PET plastic production according to claim 6, characterized in that, The surface of the support rod (81) is provided with a material distribution frame (82), which is located inside the hopper (62).

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