Conical twin screw for the production of bellows

Abstract

The application discloses a conical twin screw for corrugated pipe production, which comprises a pair of conical screws meshing with each other and having opposite rotation directions, each conical screw comprises a rod body extending from front to back and a thread spirally extending on the rod body from front to back; the rod body sequentially comprises a feeding section, a plasticizing section, an exhaust section and a metering section from front to back, and the thread comprises: first screw ridges formed in the feeding section; second screw ridges, third screw ridges and fourth screw ridges sequentially formed in the plasticizing section from front to back; fifth screw ridges formed in the exhaust section; and sixth screw ridges formed in the metering section; the first screw ridges, the third screw ridges, the fifth screw ridges and the sixth screw ridges are all provided with inclined groove groups, and each inclined groove group comprises a plurality of inclined grooves distributed along the circumferential direction of the rod body; the feeding section, the plasticizing section, the exhaust section and the metering section of the application are all provided with a plurality of inclined grooves, the shearing and mixing of high filling materials are strengthened, and thus the plasticizing effect is improved, and the production requirement of high filling materials is met.

Description

Technical Field

[0001] This application relates to the field of plastic production technology and equipment, and in particular to a conical twin-screw extruder for corrugated pipe production. Background Technology

[0002] The traditional screw structure of bellows has poor plasticizing effect, which cannot meet the needs of high-filling materials and market demands. At the same time, high-filling materials will cause the screw to wear more quickly, resulting in a shorter service life. Summary of the Invention

[0003] In order to solve the above-mentioned technical problems, the purpose of this application is to provide a tapered twin-screw for bellows production.

[0004] To achieve the above objectives, this application adopts the following technical solution: a conical twin-screw extruder for bellows production, comprising a pair of meshing conical screws with opposite directions of rotation, each conical screw comprising a rod extending from front to back and a thread extending helically from front to back on the rod, the base diameter of the rod and the outer diameter of the thread both gradually decreasing from front to back; the rod, from front to back, consists of a feeding section, a plasticizing section, an venting section, and a metering section, the lengths of the feeding section and the metering section being greater than the lengths of the plasticizing section and the venting section; the thread comprises independent threaded edges that are disconnected from each other in each segment, the thread including: a first threaded edge formed in the feeding section; a second threaded edge... The first, third, and fourth screw ridges are formed sequentially from front to back in the plasticizing section; the fifth screw ridge is formed in the venting section; and the sixth screw ridge is formed in the metering section. The first and third screw ridges are double threads, the second and fourth screw ridges are single threads, and the fifth and sixth screw ridges are three-start threads. Each of the first, third, fifth, and sixth screw ridges is provided with a set of inclined slots. Each set of inclined slots includes several inclined slots spaced apart along the circumference of the rod body, and each inclined slot has an inclined angle with the axis of the rod body. The inclined slots on the pair of tapered screws are symmetrically arranged.

[0005] In the above technical solution, it is further preferred that the tapered screw is a solid screw.

[0006] In the above technical solution, it is further preferred that the lead of the first screw edge gradually decreases from front to back, and the leads of the fifth screw edge and the sixth screw edge are both greater than the lead of the first screw edge.

[0007] In the above technical solution, it is further preferred that the plasticizing section consists of a first compression section, a remixing section and a second compression section from front to back. The length of the remixing section is greater than that of the first compression section and the second compression section. The second screw edge is distributed in the first compression section, the third screw edge is distributed in the remixing section, and the fourth screw edge is distributed in the second compression section.

[0008] In the above technical solution, it is further preferred that the thickness of the second screw edge is greater than the thickness of the fourth screw edge, and the thickness of the fourth screw edge is greater than the thickness of the third screw edge.

[0009] In the above technical solution, it is further preferred that the thickness of the fifth thread is greater than the thickness of the other threads.

[0010] In the above technical solution, it is further preferred that the inclined groove group on the first screw rib is arranged near the rear end of the feeding section; the inclined groove group on the fifth screw rib is arranged near the rear end of the exhaust section; and the inclined groove group on the sixth screw rib is arranged near the front end of the metering section.

[0011] In the above technical solution, it is further preferred that the inclination direction of each of the inclined grooves is opposite to the rotation direction of the corresponding thread.

[0012] In the above technical solution, it is further preferred that the included angle of inclination is 0°-60°.

[0013] In the above technical solution, it is further preferred that the depth and width of the inclined grooves opened on the first and third helical ridges are both greater than the depth and width of the inclined grooves opened on the fifth and sixth helical ridges.

[0014] Compared with the prior art, this application achieves the following beneficial effects:

[0015] The conical screw of this application has been structurally optimized to meet the production requirements of bellows. Multiple inclined grooves are provided in the feeding section, plasticizing section, venting section and metering section to enhance the shearing and mixing of high-filling materials, thereby improving the plasticizing effect, meeting the production requirements of high-filling materials and improving production efficiency. In addition, the solid and alloy lengthening design of the conical screw reduces wear and increases service life. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a conical twin-screw provided in an embodiment of this application;

[0017] Figure 2 for Figure 1 A schematic diagram of the structure of one of the tapered screws;

[0018] Figure 3 For along Figure 2 A sectional view cut along line AA.

[0019] Figure 4 For along Figure 2 A sectional view cut along the middle BB line;

[0020] Figure 5 For along Figure 2 A sectional view cut along the CC line;

[0021] Figure 6 For along Figure 2 A cross-sectional view cut along the DD line.

[0022] Wherein: 10. Conical screw; 1. Screw body; 11. Feeding section; 12. Plasticizing section; 121. First compression section; 122. Remixing section; 123. Second compression section; 13. Exhaust section; 14. Metering section; 2. Thread; 21. First screw ridge; 22. Second screw ridge; 23. Third screw ridge; 24. Fourth screw ridge; 25. Fifth screw ridge; 26. Sixth screw ridge; 3. First inclined groove group; 31. First inclined groove; 4. Second inclined groove group; 41. Second inclined groove; 5. Third inclined groove group; 51. Third inclined groove; 6. Fourth inclined groove group; 61. Fourth inclined groove. Detailed Implementation

[0023] To illustrate the technical content, structural features, achieved objectives, and effects of the application in detail, the technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. In the following description, for illustrative purposes, numerous specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the invention. However, various exemplary embodiments may also be implemented without these specific details or in one or more equivalent arrangements. Furthermore, the various exemplary embodiments may differ, but are not necessarily exclusive. For example, the specific shape, structure, and characteristics of the exemplary embodiments may be used or implemented in another exemplary embodiment without departing from the inventive concept.

[0024] This application provides a tapered twin-screw screw for bellows production, such as... Figure 1 As shown, it includes a pair of intermeshing conical screws 10 with opposite rotation directions. The pair of conical screws 10 rotate in opposite directions to compress, plasticize and convey the material inside the barrel.

[0025] Each conical screw 10 includes a rod body 1 extending from front to back and a thread 2 extending helically from front to back on the rod body 1. The bottom diameter D of the rod body 1 and the outer diameter W of the thread 2 both gradually decrease from front to back, so that the depth of the thread groove formed by the thread 2 on the rod body 1 gradually decreases, thereby increasing the forward conveying capacity of the conical screw 10.

[0026] like Figure 1 , 2 As shown, the rod body 1 consists of a feeding section 11, a plasticizing section 12, an venting section 13, and a metering section 14 from front to back. The lengths of the feeding section 11 and the metering section 14 are both greater than the lengths of the plasticizing section 12 and the venting section 13. The longer feeding section 11 increases the feed rate of the conical screw 10, allowing the material to be compacted in the feeding section 11 to reduce the risk of leakage and backflow during subsequent conveying. The shorter plasticizing section 12 shortens the plasticizing time of the material, avoiding overheating and scorching caused by prolonged plasticizing. The shorter venting section 13 allows sufficient distance for the material to vent, also preventing excessive material overflow due to excessive distance. The longer metering section 14 stabilizes the extrusion pressure of the material and ensures uniform extrusion of the material.

[0027] The thread 2 consists of independent threaded ridges that are disconnected from each other in each segment. The thread 2 includes: a first threaded ridge 21, formed in the feeding section 11; a second threaded ridge 22, a third threaded ridge 23, and a fourth threaded ridge 24, formed sequentially from front to back in the plasticizing section 12; a fifth threaded ridge 25, formed in the venting section 13; and a sixth threaded ridge 26, formed in the metering section 14. Among them, the first threaded ridge 21 and the third threaded ridge 23 are double threads, the second threaded ridge 22 and the fourth threaded ridge 24 are single threads, and the fifth threaded ridge 25 and the sixth threaded ridge 26 are three-start threads.

[0028] like Figure 1-3As shown, the first thread 21 of the double-threaded screw forms a deeper thread groove on the longer feed section 11. On the one hand, this increases the feed rate of the conical screw 10, thereby increasing the output of the conical twin-screw. On the other hand, it reduces the median clearance between the first thread 21s of the meshing pair of conical screws 10, thereby reducing material leakage and backflow in the feed section 11 and improving conveying efficiency. The first thread 21 has a first inclined groove group 3 near the rear end of the feed section 11. The first inclined groove group 3 includes a plurality of first inclined grooves 31 spaced apart along the circumferential direction of the rod body 1. The first inclined groove group 3 and the first screw rib 21 form a first mixing zone in the feeding section 11. The thickness and lead S1 of the first screw rib 21 in the first mixing zone are smaller than the thickness and lead S1 of the first screw rib 21 in other areas of the feeding section 11. The volume of the screw groove formed by the first screw rib 21 with a smaller lead in the feeding section 11 is smaller, so that the material is gradually compacted in the feeding section 11. The thinner first screw rib 21 and several first inclined grooves 31 of the first inclined groove group 3 cooperate to enhance the shearing and mixing capacity of the material in the feeding section 11, so that the material achieves a pre-plasticized state in the latter half of the feeding section 11, improving the plasticizing efficiency of the material on the conical screw 10, which is especially suitable for high-speed extrusion production lines.

[0029] like Figure 1 , 2 As shown in Figure 4, the plasticizing section 12 consists of a first compression section 121, a remixing section 122, and a second compression section 123 from front to back. The length of the remixing section 122 is greater than the length of the first compression section 121 and the second compression section 123. The second screw 22 is distributed in the first compression section 121, the third screw 23 is distributed in the remixing section 122, and the fourth screw 24 is distributed in the second compression section 123.

[0030] The second screw rib 22, the third screw rib 23, and the fourth screw rib 24 are disconnected from each other in the compression section 12. The thickness of the second screw rib 22 is greater than the thickness of the fourth screw rib 24, and the thickness of the fourth screw rib 24 is greater than the thickness of the third screw rib 23. The single-threaded second screw rib 22 and the fourth screw rib 24 are located on the front and rear sides of the third screw rib 23, respectively, controlling the material's residence time in the remixing section 122 and preventing the material from staying in the plasticizing section 12 for too long. A second inclined groove group 4 is formed on the third screw rib 23. The second inclined groove group 4 includes several second inclined grooves 41 spaced apart along the circumference of the rod body 1. The second inclined groove group 4 and the third screw rib 23 cooperate to form a second mixing zone in the remixing section 122. The thin third screw rib 23, in conjunction with the several second inclined grooves 41 of the second inclined groove group 4, strengthens the mixing and shearing of the material in the remixing section 122, fully plasticizes the material, and improves the plasticizing and melting effect of the material.

[0031] The lead S2 of the fifth screw ridge 25 and the lead S3 of the sixth screw ridge 26 are both greater than the lead S1 of the first screw ridge 21, which increases the volume of the screw grooves formed in the exhaust section 13 and the metering section 14.

[0032] like Figure 1 , 2 As shown in Figure 5, the thickness of the fifth screw ridge 25 is greater than that of the screw ridges in other segments, thereby reducing the shear force on the material in the exhaust section 13. The enlarged screw groove in the exhaust section 13 keeps the material in a semi-filled state, providing sufficient space for the material to be vented under the stirring of the three-headed screw. The fifth screw ridge 25 has a third inclined groove group 5 near the rear end of the exhaust section 13. The third inclined groove group 5 includes several third inclined grooves 51 spaced apart along the circumference of the rod body 1. The several third inclined grooves 51 in the rear half of the exhaust section 13 are used to enhance the stirring of the material, so that the gas and heat in the material are fully released, effectively improving the exhaust efficiency of the exhaust section 13 and effectively reducing the extrusion temperature of the material.

[0033] like Figure 1 , 2 As shown in Figure 6, the sixth screw ridge 26 has a fourth inclined groove group 6 at the front end near the metering section 14. The fourth inclined groove group 6 includes several fourth inclined grooves 61 spaced apart along the circumference of the rod body 1. The fourth inclined groove group 6 enhances the mixing and plasticizing of the material in the first half of the metering section 14, thereby improving the plasticizing effect and uniformity of the material. In the second half of the metering section 14, the positive displacement conveying capacity is enhanced by the large lead of the sixth screw ridge 26, stabilizing the conveying and establishing the extrusion pressure to overcome the die head resistance, so that the material is extruded stably and uniformly. The mating clearance of the sixth screw ridges 26 of the pair of conical screws 10 in the metering section 14 is reduced, thereby reducing the risk of leakage and backflow.

[0034] like Figure 1 As shown, the first inclined groove 31, the second inclined groove 41, the third inclined groove 51, and the fourth inclined groove 61 all have an inclined angle α with the axis X1 of the rod body 1. The inclined direction of each inclined groove is opposite to the helix direction of the corresponding thread 2, and the inclined angle is 0°-60°. The inclined grooves on the pair of conical screws 10 are symmetrically opened to each other and cooperate with each other to improve the plasticizing effect of the material on the conical twin screw and improve product quality.

[0035] like Figure 1 , 3As shown in Figures 4, 5, and 6, the first inclined trough 31 and the second inclined trough 41 are deep troughs, while the third inclined trough 51 and the fourth inclined trough 61 are shallow troughs. The width w and depth h of the deep troughs are both greater than those of the shallow troughs, resulting in higher mixing and shearing capabilities. The first inclined trough 31 and the second inclined trough 41 are located in the feeding section 11 and the compression section 12, respectively, in the front half of the conical screw 10, enhancing the mixing and shearing of the material to ensure thorough and uniform plasticization. The third inclined trough 51 and the fourth inclined trough 61 are located in the venting section 13 and the metering section 14, respectively, in the rear half of the conical screw 10, primarily enhancing the mixing of the material. The third inclined trough group 5 stirs the material in the venting section 13, allowing the gas in the material to be fully released, reducing the moisture content in the material, thereby improving the final product quality. The fourth inclined trough group 6 stirs the material in the metering section 14, ensuring uniform mixing and establishing a stable extrusion pressure, resulting in more uniform extruded material.

[0036] Both tapered screws 10 in this application are solid screws with high base material strength and are not easily worn. At the same time, the solid design increases the weight of the tapered screw, which can alleviate the upward force of the material on the screw in the front section of extrusion, avoid the screw from lifting and breaking, and effectively improve the service life of the tapered screw.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made without departing from the spirit and scope of this application. The scope of protection claimed by this application is defined by the appended claims, specification, and their equivalents.

Claims

1. A conical twin-screw for bellows production, comprising a pair of intermeshing conical screws in opposite directions of rotation, each of the conical screws comprising a shaft extending from front to back and a thread extending helically from front to back on the shaft, wherein the base diameter of the shaft and the outer diameter of the thread both gradually decrease from front to back; characterized in that, The rod body consists of a feeding section, a plasticizing section, an exhaust section, and a metering section from front to back. The lengths of the feeding section and the metering section are both greater than the lengths of the plasticizing section and the exhaust section. The thread consists of independent threaded ridges that are disconnected from each other in each segment. The thread includes: a first threaded ridge formed in the feeding section; a second, third, and fourth threaded ridges formed sequentially from front to back in the plasticizing section; a fifth threaded ridge formed in the venting section; and a sixth threaded ridge formed in the metering section. The first and third threaded ridges are double threads, the second and fourth threaded ridges are single threads, and the fifth and sixth threaded ridges are three-start threads. Each of the first, third, fifth, and sixth threaded ridges is provided with a set of inclined slots. Each set of inclined slots includes several inclined slots spaced apart along the circumference of the rod, and each inclined slot has an inclined angle with the axis of the rod. The inclined slots on the pair of tapered screws are symmetrically arranged.

2. The conical twin-screw screw according to claim 1, characterized in that, The tapered screw is a solid screw.

3. The conical twin-screw screw according to claim 1, characterized in that, The lead of the first screw edge gradually decreases from front to back, and the leads of the fifth and sixth screw edges are both greater than the lead of the first screw edge.

4. The conical twin-screw screw according to claim 1, characterized in that, The plasticizing section consists of a first compression section, a remixing section, and a second compression section from front to back. The length of the remixing section is greater than that of the first compression section and the second compression section. The second screw thread is distributed in the first compression section, the third screw thread is distributed in the remixing section, and the fourth screw thread is distributed in the second compression section.

5. The conical twin-screw screw according to claim 1, characterized in that, The thickness of the second screw edge is greater than the thickness of the fourth screw edge, and the thickness of the fourth screw edge is greater than the thickness of the third screw edge.

6. The conical twin-screw screw according to claim 1, characterized in that, The thickness of the fifth threaded edge is greater than the thickness of the other threaded edges.

7. The conical twin-screw screw according to claim 1, characterized in that, The inclined groove group on the first screw rib is arranged near the rear end of the feeding section; the inclined groove group on the fifth screw rib is arranged near the rear end of the exhaust section; and the inclined groove group on the sixth screw rib is arranged near the front end of the metering section.

8. The conical twin-screw screw according to claim 7, characterized in that, The inclination direction of each of the aforementioned grooves is opposite to the helix direction of the corresponding thread.

9. The conical twin-screw screw according to claim 8, characterized in that, The tilt angle is 0°-60°.

10. The conical twin-screw according to claim 7, characterized in that, The depth and width of the grooves opened on the first and third helical ridges are both greater than the depth and width of the grooves opened on the fifth and sixth helical ridges.

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