A twin-screw structure of an extruder

Abstract

The utility model provides a kind of double screw structure of extruder, solve the problem that material is stored in the broken area of screw of the structure of existing double screw.It also includes reverse screw, is arranged between plasticizing section and homogenizing section, the front and back two ends of the reverse screw are respectively connected with the screw on plasticizing section, homogenizing section.When material reaches the reverse screw, the material is mixed, and part of the material is returned to the plasticizing section again through the reverse screw for re-plasticizing, effectively improving the plasticizing effect, and the reverse screw has a certain thrust, the material will not stay at the reverse screw, thereby ensuring continuous discharge to improve yield by more than 20% and the quality of the extruded product is more stable and high quality.

Description

Technical Field

[0001] This utility model relates to the field of screw technology, specifically to a twin-screw structure for an extruder. Background Technology

[0002] A twin-screw extruder is a core industrial piece of equipment that uses two meshing screws to rotate in tandem, achieving material conveying, mixing, melting, shearing, and extrusion molding. Currently, the screw structure in twin-screw extruders, such as the twin-screw structure of a bamboo-plastic extruder disclosed in Chinese Patent Publication No. CN203293512U, is divided into a feeding section, a transition section, a plasticizing section, a retention section, a venting section, and an extrusion section. However, the screw threads of adjacent sections are disconnected and spaced apart. While the disconnected screw threads allow materials to flow together and mix, a small amount of material may remain in the disconnected screw threads. Over time, this material may decompose or carbonize, leading to a decline in the quality of the extruded product. Utility Model Content

[0003] To overcome the shortcomings of the prior art, this utility model provides a twin-screw structure for an extruder, which solves the problem of material retention in the broken screw section of the existing twin-screw structure.

[0004] The technical solution adopted in this utility model is as follows:

[0005] A twin-screw structure for an extruder includes a rod body, wherein the rod body is sequentially provided with a feeding section, a plasticizing section, and a homogenizing section along the material movement direction, and further includes:

[0006] A reverse spiral ridge is provided between the plasticizing section and the homogenizing section, and the front and rear ends of the reverse spiral ridge are respectively connected to the spiral ridges on the plasticizing section and the homogenizing section.

[0007] The upper and lower ends of the connection between the reverse spiral ridge and the spiral ridge on the plasticizing section and homogenizing section are both arc-shaped surfaces.

[0008] The distance from the front end to the back end of the reverse thread is 1-2 times the pitch length of the reverse thread.

[0009] The width of the reverse spiral ridge is smaller than the width of the spiral ridges on the plasticizing section and the homogenizing section.

[0010] The number of screw heads on the feeding section, plasticizing section, homogenizing section, and reverse screw head are all double-headed.

[0011] A cooling channel is provided at the center of the rod.

[0012] The rod is cylindrical or conical.

[0013] The beneficial effects of this utility model are:

[0014] The reverse screw ridges are opposite in direction to the screw ridges in the feeding section, plasticizing section, and homogenizing section. When the material reaches the reverse screw ridges, it is mixed. At the same time, some of the material returns to the plasticizing section through the reverse screw ridges for re-plasticization, which effectively improves the plasticizing effect. Moreover, the reverse screw ridges have a certain thrust, so the material will not stay at the reverse screw ridges. This ensures continuous discharge, which can increase the output by more than 20% and make the extruded product quality more stable and of higher quality. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the flat double screw of this utility model.

[0016] Figure 2 This is a utility model Figure 1 An enlarged schematic diagram of point A in the middle.

[0017] Figure 3 This is a cross-sectional schematic diagram of the present invention.

[0018] Figure 4 This is a schematic diagram of the conical twin-screw of this utility model.

[0019] 1. Rod body; 2. Feeding section; 3. Plasticizing section; 4. Homogenizing section; 5. Reverse spiral rib; 6. Arc-shaped surface; 7. Cooling channel. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0021] In the embodiments, such as Figure 1 , Figure 2 , Figure 4 As shown, a twin-screw structure for an extruder includes a screw body 1, wherein the screw body 1 is sequentially provided with a feeding section 2, a plasticizing section 3, and a homogenizing section 4 along the material movement direction, and further includes:

[0022] A reverse screw rib 5 is disposed between the plasticizing section 3 and the homogenizing section 4, and the front and rear ends of the reverse screw rib 5 are respectively connected to the screw ribs on the plasticizing section 3 and the homogenizing section 4.

[0023] The reverse screw rib 5 has the opposite spiral direction to the screw ribs on the feeding section 2, plasticizing section 3, and homogenizing section 4. When the material reaches the reverse screw rib 5, the material is mixed. At the same time, some of the material returns to the plasticizing section 3 through the reverse screw rib 5 for re-plasticization, which effectively improves the plasticizing effect. Moreover, the reverse screw rib 5 has a certain thrust, so the material will not stay at the reverse screw rib 5, thus ensuring continuous discharge, which can increase the output by more than 20% and make the extruded product quality more stable and of higher quality.

[0024] In the embodiments, such as Figure 1 , Figure 2 , Figure 4As shown, the upper and lower ends of the connection between the reverse screw rib 5 and the screw ribs on the plasticizing section 3 and homogenizing section 4 are both arc-shaped surfaces 6. The arc-shaped surface 6 is less likely to generate dead corners, making it less likely for material to accumulate and causing decomposition or carbonization.

[0025] In the embodiments, such as Figure 1 , Figure 2 , Figure 4 As shown, the distance from the front end to the back end of the reverse screw ridge 5 is 1-2 times the pitch length of the reverse screw thread 5. The material will not stay in the area of ​​the reverse screw ridge 5 for too long, to prevent the material from decomposing or carbonizing due to excessive residence time.

[0026] In the embodiments, such as Figure 1 , Figure 2 , Figure 4 As shown, the width of the reverse screw rib 5 is smaller than the width of the screw ribs on the plasticizing section 3 and the homogenizing section 4. The width of the reverse screw rib 5 is the smallest, and the reverse feeding capacity is less than the forward feeding capacity, thereby ensuring that material continuously enters the homogenizing section 4.

[0027] In the embodiments, such as Figure 1 , Figure 4 As shown, the screw threads on the feeding section 2, plasticizing section 3, homogenizing section 4, and the reverse screw thread 5 are all double-headed. Compared with single-headed screw threads, the double-headed screw has higher transmission efficiency and better load-bearing capacity.

[0028] In the embodiments, such as Figure 3 As shown, a cooling channel 7 is provided at the center of the rod body 1. Coolant is introduced into the cooling channel 7 to cool the rod body 1 and prevent the rod body 1 from overheating, which could lead to the decomposition or carbonization of the material.

[0029] In the embodiments, such as Figure 1 , Figure 4 As shown, the rod body 1 is cylindrical or conical. The reverse thread structure can be applied to both flat twin-screws and conical twin-screws.

[0030] Obviously, the above embodiments of this utility model are merely illustrative examples and not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, these obvious variations or modifications derived from the essential spirit of this utility model still fall within the protection scope of this utility model.

Claims

1. A twin-screw structure for an extruder, comprising a screw body (1), wherein the screw body (1) is sequentially provided with a feeding section (2), a plasticizing section (3), and a homogenizing section (4) along the material movement direction, characterized in that, Also includes: A reverse screw rib (5) is provided between the plasticizing section (3) and the homogenizing section (4), and the front and rear ends of the reverse screw rib (5) are respectively connected to the screw ribs on the plasticizing section (3) and the homogenizing section (4).

2. The twin-screw structure of an extruder as described in claim 1, characterized in that: The upper and lower ends of the connection between the reverse spiral edge (5) and the spiral edge on the plasticizing section (3) and homogenizing section (4) are both arc-shaped surfaces (6).

3. The twin-screw structure of an extruder as described in claim 1, characterized in that: The distance from the front end to the end of the reverse thread (5) is 1-2 times the pitch length of the reverse thread.

4. The twin-screw structure of an extruder as described in claim 1, characterized in that: The width of the reverse spiral ridge (5) is smaller than the width of the spiral ridges on the plasticizing section (3) and the homogenizing section (4).

5. The twin-screw structure of an extruder as described in claim 1, characterized in that: The number of screw threads on the feeding section (2), plasticizing section (3), homogenizing section (4) and the number of reverse screw threads (5) are all double.

6. The twin-screw structure of an extruder as described in claim 1, characterized in that: A cooling channel (7) is provided at the center of the rod (1).

7. The twin-screw structure of an extruder as described in claim 1, characterized in that: The rod (1) is cylindrical or conical.

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