Extrusion pelletizing device for foaming materials

Abstract

The invention discloses a foaming material extruding and pelletizing device which comprises a machine base, an extruding cylinder is installed on the machine base, an extruding screw is installed in the extruding cylinder, a feeding device and a foaming agent adding device are arranged on the extruding cylinder, a screw driving device is installed on the machine base, a die head is arranged at the downstream end of the extruding cylinder, and an extruding hole is formed in the die head. A mounting shaft is arranged on the die head, a pelletizing cutter holder is rotationally mounted on the mounting shaft, a cutter holder driving device is mounted on the machine base, pelletizing blades are fixedly mounted on the pelletizing cutter holder, the cutting edge covers the extrusion hole and comprises an inner cutting edge surface and an outer cutting edge surface, a gap adjusting device is mounted on the mounting shaft, and a material receiving and conveying device is further mounted on the machine base. According to the extrusion pelletizing device, foaming materials extruded by an extruder can be more rapidly cut, the situation of knife sticking is avoided, and therefore the requirement for rapid pelletizing of the foaming materials is met.

Description

Technical Field

[0001] The invention relates to the technical field of plastic machines, in particular to an extrusion and pelletizing device for foaming materials. Background Art

[0002] In the plastic extrusion industry, the extruder is a commonly used plastic machine. The extruder relies on the pressure and shear force generated by the rotation of the screw to fully plasticize and evenly mix the material, then extrude it through the die head and pelletize it using a pelletizing device.

[0003] Polylactic acid (PLA) is a synthetic material made from corn, wheat and other starches, which are fermented into lactic acid, polymerized and spun. This material is biodegradable, making it a new emerging material that can be widely used in daily life. PLA foamed material formed by adding a foaming agent to PLA can be used as a filler.

[0004] At present, conventional extrusion pelletizing devices mainly have an axially sliding sliding base downstream of the extruder, on which a motor for driving the pelletizing tool to rotate is fixedly installed. When in use, the pelletizing tool is fitted on the plane of the die head by axially sliding the base, and then the motor is started to drive the pelletizing tool to rotate, thereby pelletizing the melt extruded by the extruder.

[0005] However, in the process of foaming materials, taking PLA as an example, PLA raw materials and foaming agents are added to the extruder together. After being heated and plasticized by the extruder, they will expand and foam when extruded from the extrusion hole of the die head. The extrusion speed of this material is very fast, and the extruded material has a certain viscosity. Therefore, when a conventional pelletizing device is used for pelletizing, the cutting edge of the pelletizing blade will adhere to the material during fast cutting, and the material becomes more and more sticky, which will eventually lead to the situation that it cannot be cut continuously.

[0006] In addition, the current pelletizing tool is matched with the die head by sliding a sliding base, and the matching gap between the pelletizing tool and the die head cannot be accurately adjusted. This also leads to the inability to accurately adjust the gap of the pelletizing tool when cutting PLA foaming materials, and also causes the material to stick to the tool.

[0007] In addition, the extrusion speed of this extruder is very fast. Therefore, the material after extrusion has new requirements for discharge, which requires fast discharge. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide an extrusion pelletizing device for foaming materials, which can cut the foaming materials extruded by the extruder more quickly and avoid the occurrence of knife sticking, thereby meeting the requirement of rapid pelletizing of the foaming materials.

[0009] In order to solve the above technical problems, the technical solution of the present invention is: an extrusion and pelletizing device for foaming materials, comprising a machine base, an extrusion barrel is fixedly installed on the machine base, an extrusion screw is rotatably installed in the extrusion barrel, a feeding device and a foaming agent adding device are arranged on the extrusion barrel, a screw driving device for driving the extrusion screw to rotate is installed on the machine base, a die head is arranged at the downstream end of the extrusion barrel, an extrusion hole is arranged on the die head, a mounting shaft is fixedly arranged on the die head, a pelletizer seat is rotatably installed on the mounting shaft, and a device for driving the pelletizer seat to rotate is installed on the machine base. A knife seat driving device, a plurality of pelletizing blades are fixedly mounted on the pelletizing knife seat, the blades of the pelletizing blades cover the extrusion holes of the die head, the blades of the pelletizing blades include an inner blade surface close to the die head and an outer blade surface away from the die head, an inner angle is formed between the inner blade surface and the plane of the die head, an outer angle is formed between the outer blade surface and the plane of the die head, and both the inner angle and the outer angle are acute angles; a gap adjusting device for adjusting the gap between the blade of the pelletizing blade and the die head is mounted on the mounting shaft, and a material receiving and conveying device for receiving particles cut by the pelletizing blade is also mounted on the machine seat.

[0010] As a preferred solution, the gap adjustment device includes an adjusting screw sleeve threadedly mounted on the mounting shaft, the adjusting screw sleeve is located on the outside of the pelletizer seat, and a compression spring is mounted on the mounting shaft, and the elastic force of the compression spring forces the pelletizer seat to rest against the adjusting screw sleeve.

[0011] As a preferred solution, the pelletizing blade includes a blade body and a connecting part, the blade body is provided with the cutting edge, the connecting part is provided with an axial adjustment groove, a fixing screw is installed in the axial adjustment groove, and the fixing screw fixes the connecting part to the pelletizing blade seat.

[0012] As a preferred solution, a central raised plane is provided on the plane of the die head, and the extrusion hole is within the range of the central raised plane.

[0013] As a preferred solution, the material receiving and conveying device includes a material receiving hopper fixed on the machine base, the material receiving hopper is located below the pelletizer seat, the material receiving hopper is provided with a cover covering the pelletizer seat and the pelletizer blade, the bottom of the material receiving hopper is connected to a discharge pipe, and the discharge pipe is connected to a discharge fan.

[0014] As a preferred solution, a closing pipe section is provided on the discharge pipe upstream of the receiving hopper.

[0015] As a preferred solution, the closing pipe section includes an upstream connecting flange, a downstream connecting flange and a closing pipe section body located between the upstream connecting flange and the downstream connecting flange, and the neck cross-sectional area of ​​the closing pipe section body is half of the cross-sectional area of ​​the discharge pipe.

[0016] As a preferred solution, there are two extrusion screws arranged horizontally and in parallel, and the extrusion screw includes a feeding section, a first compression section, a second compression section and a mixing section. The pitch of the spiral blades of the feeding section, the first compression section, the second compression section and the mixing section gradually decreases, and the spiral blades of the mixing section are provided with grooves.

[0017] As a preferred solution, the die head includes a die head fixing plate and a die hole plate, the die head fixing plate is fixed to the downstream end of the extrusion barrel by bolts, the downstream end of the die head fixing plate is provided with a mounting cavity, the die hole plate is provided with an embedding protrusion embedded in the mounting cavity, a filter hole plate is installed in the mounting cavity, the embedding protrusion of the die hole plate is inserted into the mounting cavity and fixed to the die head fixing plate by bolts, the extrusion hole is provided on the die hole plate and is connected with the inner cavity of the extrusion barrel through the mounting cavity.

[0018] After adopting the above technical scheme, the effect of the present invention is as follows: since an extrusion barrel is fixedly installed on the machine base, an extrusion screw is rotatably installed in the extrusion barrel, a feeding device and a foaming agent adding device are arranged on the extrusion barrel, a screw driving device for driving the extrusion screw to rotate is installed on the machine base, a die head is arranged at the downstream end of the extrusion barrel, an extrusion hole is arranged on the die head, a mounting shaft is fixedly installed on the die head, a pelletizer seat is rotatably installed on the mounting shaft, a knife seat driving device for driving the pelletizer seat to rotate is installed on the machine base, a plurality of pelletizer blades are fixedly installed on the pelletizer seat, the blades of the pelletizer blades cover the extrusion hole of the die head, and the blades of the pelletizer blades include a blade close to the die head. The inner blade surface of the head and the outer blade surface away from the die head, the inner blade surface and the plane of the die head form an inner angle, the outer blade surface and the plane of the die head form an outer angle, and the inner angle and the outer angle are both acute angles; the mounting shaft is equipped with a gap adjustment device for adjusting the gap between the blade of the pelletizing blade and the die head, and the machine base is also equipped with a material receiving and conveying device for receiving the particles cut by the pelletizing blade. Therefore, the extrusion pelletizing device fixes the pelletizing knife seat directly on the die head through the mounting shaft, and then the pelletizing blade adjusts the gap through the gap adjustment device, so as to optimize the cutting gap, and the foaming material will expand in volume after being extruded through the extrusion hole. After the expansion and pelletizing, the particle and air surface become larger, so the material will cool quickly. The inner angle is formed between the inner blade surface and the plane of the die head, and the pelletizing blade only has the blade close to the die head, and the material will not adhere to the inner blade surface during pelletizing, so that the pelletizing blade can meet the extrusion pelletizing requirements of the foaming material, and the pelletized material is sent out through the material receiving and conveying device.

[0019] Furthermore, since the gap adjustment device includes an adjusting screw sleeve threadedly mounted on the mounting shaft, the adjusting screw sleeve is located on the outer side of the pelletizer seat, and a compression spring is mounted on the mounting shaft, the elastic force of the compression spring forces the pelletizer seat to lean against the adjusting screw sleeve, and the adjusting screw sleeve can be rotated to axially squeeze the pelletizer seat so that the blade is close to the plane of the die head, thereby reducing the gap. When the gap needs to be increased, the adjusting screw sleeve is rotated in the opposite direction, and the compression spring forces the pelletizer seat to always contact the adjusting screw sleeve, so that the blade is always kept at a suitable gap, which is convenient for pelletizing without sticking.

[0020] Furthermore, since the pelletizer blade includes a blade body and a connecting portion, the blade body is provided with the blade edge, the connecting portion is provided with an axial adjustment groove, a fixing screw is installed in the axial adjustment groove, and the fixing screw fixes the connecting portion to the pelletizer seat. The axial adjustment groove can facilitate the adjustment of the fixed position of the connecting portion, thereby adjusting the position of the pelletizer blade.

[0021] Since a central raised plane is arranged on the plane of the die head, the extrusion hole is within the range of the central raised plane, thus reducing the contact area between the blade and the plane of the die head and avoiding the wear of the blade.

[0022] Furthermore, the material receiving and conveying device includes a receiving hopper fixed on the machine base, the receiving hopper is located below the pelletizer seat, the receiving hopper is provided with a cover that covers the pelletizer seat and the pelletizer blade, the bottom of the receiving hopper is connected with a discharge pipe, the discharge pipe is connected with a discharge fan, and a closing pipe section is provided on the discharge pipe upstream of the receiving hopper. The closing pipe section includes an upstream connecting flange, a downstream connecting flange and a closing pipe section body located between the upstream connecting flange and the downstream connecting flange, and the neck cross-sectional area of ​​the closing pipe section body is half of the cross-sectional area of ​​the discharge pipe. Therefore, the material receiving and conveying device uses a fan to blow the material out of the discharge pipe, and the closing pipe section is provided upstream, which can increase the flow rate of the airflow, so that the particles can be quickly taken away to avoid accumulation, and the cover can prevent splashing during rapid pelletizing.

[0023] Furthermore, since the die head includes a die head fixing plate and a die hole plate, the die head fixing plate is fixed to the downstream end of the extrusion barrel by bolts, the downstream end of the die head fixing plate is provided with a mounting cavity, the die hole plate is provided with an embedding protrusion embedded in the mounting cavity, a filter hole plate is installed in the mounting cavity, the embedding protrusion of the die hole plate is inserted into the mounting cavity, and is fixed to the die head fixing plate by bolts, the extrusion hole is provided on the die hole plate and is connected with the inner cavity of the extrusion barrel through the mounting cavity, the die head utilizes the filter hole plate to filter impurities in the material, and it is also convenient to disassemble, replace or clean the filter hole plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0025] Figure 1 is a schematic structural diagram of an embodiment of the present invention;

[0026] Figure 2 is a structural schematic diagram of another angle of an embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of an embodiment of the present invention in which some structures are omitted;

[0028] Figure 4 Schematic diagram of the structure of the pelletizing part of an embodiment of the present invention;

[0029] Figure 5 yes Figure 4 Right view of;

[0030] Figure 6 yes Figure 5 Structural cross-section along AA;

[0031] Figure 7 2 is a schematic structural diagram of a pelletizing knife seat according to an embodiment of the present invention;

[0032] Figure 8 It is a schematic structural diagram of a particle conveying device according to an embodiment of the present invention;

[0033] Fig. 9 is a schematic structural diagram of an extrusion screw according to an embodiment of the present invention;

[0034] In the attached drawings: 1. base; 2. extruder barrel; 3. extruder screw; 310 feeding section; 32. first compression section; 33. second compression section; 34. mixing section; 35. groove; 4. feeding device; 5. foaming agent adding device; 6. mounting shaft; 7. pelletizing knife seat; 8. knife seat driving device; 9. screw driving device; 10. pelletizing blade; 101. inner blade surface; 102. outer blade surface; 103. connecting part; 104. Fixed screw; 11. Adjusting screw sleeve; 12. Compression spring; 13. Central raised platform; 14. Receiving hopper; 15. Cover; 16. Discharge pipe; 17. Discharge fan; 18. Closing pipe section; 181. Upstream connecting flange; 182. Downstream connecting flange; 183. Closing pipe section body; 19. Die head fixing plate; 20. Die hole plate; 21. Install sink cavity; 22. Embedded protrusion; 23. Filter hole plate; 24. Extrusion hole. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below through specific examples.

[0036] like Figure 1-9As shown, an extrusion pelletizing device for foaming materials comprises a machine base 1, an extrusion barrel 2 is fixedly mounted on the machine base 1, an extrusion screw 3 is rotatably mounted in the extrusion barrel 2, a feeding device 4 and a foaming agent adding device 5 are arranged on the extrusion barrel 2, a screw driving device 9 for driving the extrusion screw 3 to rotate is installed on the machine base 1, a die head is arranged at the downstream end of the extrusion barrel 2, an extrusion hole 24 is arranged on the die head, a mounting shaft 6 is fixedly arranged on the die head, a pelletizing knife seat 7 is rotatably mounted on the mounting shaft 6, a knife seat driving device 8 for driving the pelletizing knife seat 7 to rotate is installed on the machine base 1, and a pelletizing knife seat 7 is fixedly mounted on the pelletizing knife seat 7. A plurality of pelletizing blades 10, the blades of the pelletizing blades 10 cover the extrusion holes 24 of the die head, the blades of the pelletizing blades 10 include an inner blade surface 101 close to the die head and an outer blade surface 102 away from the die head, an inner angle is formed between the inner blade surface 101 and the plane of the die head, and an outer angle is formed between the outer blade surface 102 and the plane of the die head, both the inner angle and the outer angle are acute angles, in this embodiment, the angle of the inner angle is set to 10-20°, of course, the inner angle can also be set to other angles according to requirements, the number of the pelletizing blades 10 is four, and they are evenly distributed around the pelletizing blade seat 7. A gap adjustment device for adjusting the gap between the blade of the pelletizing blade 10 and the die head is installed on the mounting shaft 6, and a material receiving and conveying device for receiving particles cut by the pelletizing blade 10 is also installed on the machine base 1.

[0037] In this embodiment, the die head includes a die head fixing plate 19 and a die hole plate 20, the inner blade surface 101 and the die hole plate 20 form the above-mentioned inner angle, the outer blade surface 102 and the die hole plate 20 form the above-mentioned outer angle, the die head fixing plate 19 is fixed to the downstream end of the extrusion barrel 2 by bolts, and the downstream end of the die head fixing plate 19 is provided with a mounting cavity 21, the die hole plate 20 is provided with an embedding protrusion 22 embedded in the mounting cavity 21, and a filter plate 23 is installed in the mounting cavity 21. The embedding protrusion 22 of the die hole plate 20 is inserted into the mounting cavity 21 and fixed to the die head fixing plate 19 by bolts, and the extrusion hole 24 is provided on the die hole plate 20 and communicates with the inner cavity of the extrusion barrel 2 through the mounting cavity 21. Among them, the die hole plate 20 is provided with a central raised plane 13, and the extrusion hole 24 is within the range of the central raised plane 13.

[0038] In this embodiment, the gap adjustment device includes an adjusting screw sleeve 11 threadedly mounted on the mounting shaft 6, the adjusting screw sleeve 11 is located on the outside of the pelletizer seat 7, and a compression spring 12 is sleeved on the mounting shaft 6. The elastic force of the compression spring 12 forces the pelletizer seat 7 to abut against the adjusting screw sleeve 11;

[0039] The receiving and conveying device comprises a receiving hopper 14 fixed on the machine base 1, the receiving hopper 14 is located below the pelletizing knife seat 7, and a cover 15 covering the pelletizing knife seat 7 and the pelletizing blade 10 is provided on the receiving hopper 14. Figure 1 and 2The cover 15 is in an open state, and a discharge pipe 16 is connected to the bottom of the hopper 14, and the discharge pipe 16 is connected to a discharge fan 17;

[0040] The knife seat driving device 8 includes a knife seat driving motor, and a pulley is provided on the pelletizing knife seat 7. The knife seat driving motor drives the pelletizing knife seat 7 to rotate through the pulley. The pelletizing knife seat 7 is provided with a first bearing mounting hole and a second bearing mounting hole. The first bearing is installed in the first bearing mounting hole with clearance fit, and the second bearing is embedded and fixed in the second bearing mounting hole. The first bearing is closer to the die head than the second bearing. The inner rings of the first bearing and the second bearing are sleeved on the mounting shaft 6. One end of the compression spring 12 presses on the first bearing, and the other end presses on the second bearing. The pelletizing knife seat 7 is provided with a plurality of mounting planes, and the connecting portion 103 is fixed on the mounting planes by at least two fixing screws 104 in a one-to-one correspondence. The pelletizing blade 10 includes a blade body and a connecting portion 103. The blade body is provided with the inner blade surface 101 and the outer blade surface 102 of the blade. The connecting portion 103 is provided with an axial adjustment groove, and a fixing screw 104 is installed in the axial adjustment groove. The fixing screw 104 fixes the connecting portion 103 on the pelletizing knife seat 7.

[0041] In this embodiment, a closing pipe section 18 is provided on the discharge pipe 16 upstream of the receiving hopper 14. The closing pipe section 18 includes an upstream connecting flange 181, a downstream connecting flange 182, and a closing pipe section body 183 located between the upstream connecting flange 181 and the downstream connecting flange 182, and the neck cross-sectional area of ​​the closing pipe section body 183 is half of the cross-sectional area of ​​the discharge pipe 16.

[0042] In this embodiment, there are two extrusion screws 3 and they are arranged horizontally and in parallel. The extrusion screw 3 includes a feeding section 31, a first compression section 32, a second compression section 33 and a mixing section 34. The pitch of the spiral blades of the feeding section 31, the first compression section 32, the second compression section 33 and the mixing section 34 gradually decreases, and a groove 35 is provided on the spiral blade of the mixing section 34. In addition, an electric heating sleeve is provided on the outside of the extrusion barrel 2.

[0043] The extrusion pelletizing device fixes the pelletizer seat 7 directly on the die head through the mounting shaft 6, and the pelletizer blade 10 is fixed on the pelletizer seat 7. Then, the pelletizer blade 10 is adjusted through the gap adjustment device. By adjusting the position of the fixing screw 104 in the axial adjustment groove, the connecting part 103 is adjusted to a suitable fixed position. The elastic force of the compression spring 12 forces the pelletizer seat 7 to abut against the adjusting screw sleeve 11. The adjusting screw sleeve 11 is rotated to axially squeeze the pelletizer seat 7 so that the blade is close to the die hole plate 20, thereby reducing the gap. When the gap needs to be enlarged, the adjusting screw sleeve 11 is rotated in the reverse direction. The screw sleeve 11 and the compression spring 12 will force the pelletizer seat 7 to always contact with the adjusting screw sleeve 11, so that the blade is always kept at an appropriate gap, optimizing the gap during the cutting process. During operation, the screw driving device 9 drives the extrusion screw 3 to rotate, the knife seat driving device 8 drives the pelletizer seat 7 to rotate through the pulley, the feeding device 4 feeds, and the foaming agent adding device 5 adds the foaming agent. The foaming material passes through the extrusion screw 3 and is extruded through the extrusion hole 24. At this time, the volume of the foaming material expands. After the expansion and pelletizing, the surface between the particles and the air becomes larger, so the foaming material will cool down quickly. In addition, an inner angle is formed between the inner blade surface 101 and the die hole plate 20, so that only the blade of the pelletizing blade 10 is close to the die head, and the material will not adhere to the inner blade surface 101 during pelletizing. In this way, the pelletizing blade 10 can meet the extrusion pelletizing requirements of the foaming material. The pelletized material enters the receiving hopper 14, and the discharge fan 17 blows air. After the material is cooled, it is blown out through the discharge pipe 16. In addition, the neck section of the closing pipe section 18 and other structural settings can increase the flow rate of the airflow and quickly take the material away.

[0044] The gas circuit system, actuators such as servo motors, gear transmission mechanisms, and lead screw nut mechanisms mentioned in this embodiment are all current conventional technologies. The specific structures and principles and other designs of cylinders, motors, and other transmission mechanisms are disclosed in detail in the "Mechanical Design Manual, Fifth Edition", the 28th printing of the fifth edition in Beijing in April 2008, which belongs to the prior art and its structure is clear. The SMC training textbook "Modern Practical Pneumatic Technology, 3rd Edition" published by the Machinery Industry Press on August 1, 2008 discloses vacuum components, gas circuits, and program control in detail, indicating that the gas circuit structure in this embodiment is also an existing technology and is clear. The book "Motor Drive and Speed ​​Regulation" published by the Chemical Industry Press on July 1, 2015 also introduces the control of the motor and the travel switch in detail. Therefore, the circuit and gas circuit connections are clear.

[0045] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Various modifications and alterations to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the scope of protection defined by the claims of the present invention.

Claims

1. An extrusion pelletizing device for foaming materials, comprising a machine base, an extrusion barrel is fixedly mounted on the machine base, an extrusion screw is rotatably mounted in the extrusion barrel, a feeding device and a foaming agent adding device are arranged on the extrusion barrel, and a screw driving device for driving the extrusion screw to rotate is installed on the machine base, characterized in that: A die head is provided at the downstream end of the extrusion barrel, an extrusion hole is provided on the die head, a mounting shaft is fixedly provided on the die head, a pelletizer seat is rotatably mounted on the mounting shaft, a knife seat driving device for driving the pelletizer seat to rotate is installed on the machine base, a plurality of pelletizer blades are fixedly mounted on the pelletizer seat, the blades of the pelletizer blades cover the extrusion hole of the die head, the blades of the pelletizer blades include an inner blade surface close to the die head and an outer blade surface away from the die head, an inner angle is formed between the inner blade surface and the plane of the die head, an outer angle is formed between the outer blade surface and the plane of the die head, and both the inner angle and the outer angle are acute angles; a gap adjusting device for adjusting the gap between the blade of the pelletizer blade and the die head is installed on the mounting shaft, and a material receiving and conveying device for receiving particles cut by the pelletizer blade is also installed on the machine base.

2. The extrusion and pelletizing device for a foaming material according to claim 1, characterized in that: The gap adjustment device includes an adjusting screw sleeve threadedly mounted on the mounting shaft, the adjusting screw sleeve is located on the outside of the pelletizer seat, and a compression spring is sleeved on the mounting shaft, the elastic force of the compression spring forces the pelletizer seat to rest against the adjusting screw sleeve.

3. The extrusion and pelletizing device for a foaming material according to claim 2, characterized in that: The pelletizing blade comprises a blade body and a connecting portion, wherein the blade body is provided with the blade edge, and the connecting portion is provided with an axial adjustment groove, in which a fixing screw is installed, and the fixing screw fixes the connecting portion to the pelletizing blade seat.

4. The extrusion and pelletizing device for a foaming material according to claim 3, characterized in that: A central raised plane is arranged on the plane of the die head, and the extrusion hole is within the range of the central raised plane.

5. The extrusion and pelletizing device for foaming materials according to claim 1, characterized in that: The material receiving and conveying device includes a material receiving hopper fixed on the machine base, the material receiving hopper is located below the pelletizer seat, a cover for covering the pelletizer seat and the pelletizer blade is provided on the material receiving hopper, a discharge pipe is connected to the bottom of the material receiving hopper, and a discharge fan is connected to the discharge pipe.

6. The extrusion and pelletizing device for foaming materials according to claim 5, characterized in that: The discharge pipe is provided with a closing pipe section upstream of the receiving hopper.

7. The extrusion and pelletizing device for foaming material according to claim 6, characterized in that: The closing pipe section comprises an upstream connecting flange, a downstream connecting flange and a closing pipe section body located between the upstream connecting flange and the downstream connecting flange, and the neck cross-sectional area of ​​the closing pipe section body is half of the cross-sectional area of ​​the discharge pipe.

8. The extrusion and pelletizing device for foaming material according to claim 7, characterized in that: There are two extrusion screws arranged horizontally and in parallel. The extrusion screw comprises a feeding section, a first compression section, a second compression section and a mixing section. The pitch of the spiral blades of the feeding section, the first compression section, the second compression section and the mixing section gradually decreases, and grooves are provided on the spiral blades of the mixing section.

9. The extrusion and pelletizing device for foaming materials according to any one of claims 1 to 8, characterized in that: The die head includes a die head fixing plate and a die hole plate, the die head fixing plate is fixed to the downstream end of the extrusion barrel by bolts, the downstream end of the die head fixing plate is provided with a mounting cavity, the die hole plate is provided with an embedding protrusion embedded in the mounting cavity, a filter hole plate is installed in the mounting cavity, the embedding protrusion of the die hole plate is inserted into the mounting cavity, and is fixed to the die head fixing plate by bolts, the extrusion hole is provided on the die hole plate and is connected with the inner cavity of the extrusion barrel through the mounting cavity.

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