Screw rod

Abstract

A screw comprises a feeding section, a melting compression section and an extrusion section which are sequentially connected in the conveying direction, a double-screw-flight structure is machined on the peripheral face of the melting compression section and comprises a first screw flight and a second screw flight, and a first screw groove and a second screw groove are defined by the first screw flight and the second screw flight on the two sides of the first screw flight. The width of the first screw groove is smaller than that of the second screw groove, the depth of the first screw groove is gradually increased from the feeding section to the extrusion section, and the depth of the second screw groove is gradually reduced from the feeding section to the extrusion section. According to the screw rod structure, the double-screw-edge structure is arranged on the melting compression section, the first screw groove and the second screw groove with the continuously-changing depths are formed, materials are extruded and flow back and forth between the first screw groove and the second screw groove in the conveying process, the materials are fully mixed, and the product quality is effectively improved.

Description

Technical Field

[0001] The utility model relates to a screw. Background Art

[0002] The screw is one of the core components of the extrusion equipment. Its main function is to convert solid plastic particles or powders into a stable and uniform plastic melt through steps such as conveying and compressing, compression melting, and homogenization and metering, and then output it to the die head and auxiliary equipment to produce products that meet the requirements.

[0003] In the structure of the existing single-screw extruder, the raw materials are extruded and mixed within the length of a single screw. Due to the limitation of the screw length, it is easy to cause insufficient mixing of the raw materials, affecting the product quality. Summary of the Utility Model

[0004] In view of the deficiencies in the above problems, the utility model provides a screw.

[0005] To achieve the above object, the utility model provides a screw, which includes a feeding section, a melting and compression section, and an extrusion section connected in sequence along the conveying direction. A double-threaded structure is formed on the outer peripheral surface of the melting and compression section. The double-threaded structure includes a first thread and a second thread. First screw grooves and second screw grooves are formed between the two sides of the first thread and between the first thread and the second thread. The width of the first screw groove is smaller than that of the second screw groove. The depth of the first screw groove gradually increases from the feeding section to the extrusion section, and the depth of the second screw groove gradually decreases from the feeding section to the extrusion section.

[0006] As a further improvement of the utility model, the width of the first screw groove gradually increases from the feeding section to the extrusion section, and the width of the second screw groove gradually increases from the feeding section to the extrusion section.

[0007] As a further improvement of the utility model, the first screw groove is arranged on one side of the first thread facing the feeding section, and the second screw groove is arranged on one side of the first thread facing the extrusion section.

[0008] As a further improvement of the utility model, the crest width of the first thread is greater than that of the second thread.

[0009] As a further improvement of the utility model, the crest height of the first thread is greater than that of the second thread.

[0010] The beneficial effects of the utility model are as follows:

[0011] By arranging a double-threaded rib structure on the melting and compression section, a first thread groove and a second thread groove are enclosed between the first thread rib and the second thread rib. The widths and depths of the first thread groove and the second thread groove are in a changing state. Moreover, the depth of the first thread groove gradually increases along the conveying direction, the depth of the second thread groove gradually decreases along the conveying direction, and the depth difference between the first thread groove and the second thread groove changes continuously, prompting the material to be squeezed and flow back and forth between the first thread groove and the second thread groove during the conveying process, which helps the full mixing of the material and effectively improves the quality of the product. Brief Description of the Drawings

[0012] Figure 1 is the front view of a screw of the present utility model;

[0013] Figure 2 is the schematic plane development view of a screw of the present utility model;

[0014] Figure 3 is Figure 2 the cross-sectional view taken along the line A-A in

[0015] In the figure: 1, feeding section; 2, melting and compression section; 21, first thread rib; 22, second thread rib; 23, first thread groove; 24, second thread groove; 3, extrusion section. Detailed Description of the Embodiment

[0016] As Figure 1-2 shown, a screw of the present utility model includes a feeding section 1, a melting and compression section 2, and an extrusion section 3 that are sequentially connected along the conveying direction. An extrusion head (not shown in the figure) is installed at the end of the extrusion section 3. A double-threaded rib structure is processed on the outer peripheral surface of the melting and compression section 2. The double-threaded rib structure includes a first thread rib 21 and a second thread rib 22. The crest width of the first thread rib 21 is greater than that of the second thread rib 22, and the crest height of the first thread rib 21 is greater than that of the second thread rib 22. A first thread groove 23 and a second thread groove 24 are enclosed between the two sides of the first thread rib 21 and between the first thread rib 21 and the second thread rib 22. The first thread groove 23 is arranged on the side of the first thread rib 21 facing the feeding section 1, and the second thread groove 24 is arranged on the side of the first thread rib 21 facing the extrusion section 3. The width of the first thread groove 23 is smaller than that of the second thread groove 24. The width of the first thread groove 23 gradually increases from the feeding section 1 to the extrusion section 3, the depth of the first thread groove 23 gradually increases from the feeding section 1 to the extrusion section 3, the width of the second thread groove 24 gradually increases from the feeding section 1 to the extrusion section 3, and the depth of the second thread groove 24 gradually decreases from the feeding section 1 to the extrusion section 3 (see Figure 3 ).

[0017] By arranging a double-threaded rib structure on the melting compression section, a first thread groove and a second thread groove are enclosed between the first thread rib and the second thread rib. The widths and depths of the first thread groove and the second thread groove are in a changing state. Moreover, the depth of the first thread groove gradually increases along the conveying direction, the depth of the second thread groove gradually decreases along the conveying direction, and the depth difference between the first thread groove and the second thread groove is constantly changing, which promotes the material to be extruded back and forth between the first thread groove and the second thread groove during the conveying process, contributing to the full mixing of the material and effectively improving the quality of the product.

[0018] During specific use, for the convenience of understanding the present utility model, it is described in conjunction with the accompanying drawings;

[0019] When the screw works, the screw pushes the material from the feeding section to the melting compression section for full mixing, and then extrudes it through the extrusion section; when the material moves to the melting compression section, the first thread rib mainly plays a conveying role. The crest height of the second thread rib is designed to be less than that of the first thread rib. A first thread groove and a second thread groove are enclosed between the first thread rib and the second thread rib. Within one pitch of the first thread rib, due to the obstruction of the second thread rib, the material alternately flows between the first thread groove and the second thread groove on both sides of the second thread rib, forming a turbulent state. The widths and depths of the first thread groove and the second thread groove are in a constantly changing state. The depth of the first thread groove gradually increases along the conveying direction, the depth of the second thread groove gradually decreases along the conveying direction, and the depth difference between the first thread groove and the second thread groove also gradually increases along the conveying direction, increasing the compression ratio during material conveying and accelerating the melting and mixing of the material.

[0020] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. For those skilled in the art, the present utility model can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A screw, characterized in that: It includes a feeding section (1), a melting and compression section (2), and an extrusion section (3) connected in sequence along the conveying direction. A double-screw rib structure is formed on the outer peripheral surface of the melting and compression section (2). The double-screw rib structure includes a first screw rib (21) and a second screw rib (22). First screw grooves (23) and second screw grooves (24) are enclosed between both sides of the first screw rib (21) and between the first screw rib (21) and the second screw rib (22). The width of the first screw groove (23) is smaller than that of the second screw groove (24). The depth of the first screw groove (23) gradually increases from the feeding section (1) towards the extrusion section (3), and the depth of the second screw groove (24) gradually decreases from the feeding section (1) towards the extrusion section (3).

2. A screw according to claim 1, wherein: The width of the first screw groove (23) gradually increases from the feeding section (1) towards the extrusion section (3), and the width of the second screw groove (24) gradually increases from the feeding section (1) towards the extrusion section (3).

3. A screw according to claim 1, wherein: The first screw groove (23) is provided on one side of the first screw rib (21) facing the feeding section (1), and the second screw groove (24) is provided on one side of the first screw rib (21) facing the extrusion section (3).

4. A screw according to claim 1, characterized in that: The crest width of the first screw rib (21) is greater than that of the second screw rib (22).

5. A screw according to claim 1, characterized in that: The crest height of the first screw rib (21) is greater than that of the second screw rib (22).

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