Extrusion pelletizing device for foaming materials

Abstract

The utility model discloses an extrusion pelletizing device for foaming materials, which comprises a base, an extrusion cylinder mounted on the base, an extrusion screw mounted in the extrusion cylinder, a feeding device and a foaming agent adding device arranged on the extrusion cylinder, a screw driving device mounted on the base, a die head arranged at the downstream end of the extrusion cylinder, and an extrusion hole 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 utility model 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, and then extrude it through the die head and use the pelletizer to pelletize it.

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

[0004] The current conventional extrusion pelletizing device mainly sets an axially sliding sliding base downstream of the extruder, and a motor that drives the pelletizing tool to rotate is fixedly installed on the sliding base. 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 using a conventional pelletizing device for pelletizing, the cutting edge of the pelletizing blade will adhere to the material during rapid cutting, and the material will become more and more sticky, which will eventually lead to the situation that it cannot be cut.

[0006] In addition, the current pelletizing tool is matched with the die head by sliding a sliding base. 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 foam 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. Utility Model Content

[0008] The technical problem to be solved by the utility model is to provide an extrusion and 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 requirements of rapid pelletizing of foaming materials.

[0009] In order to solve the above technical problems, the technical solution of the utility model 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 provided 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 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 installed on the mounting shaft, and a device for driving the pelletizer seat to rotate is installed on the machine base. A rotating knife seat driving device is provided, and a plurality of pelletizing blades are fixedly mounted on the pelletizing knife seat, and the blades of the pelletizing blades cover the extrusion hole 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, and 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 installed on the mounting shaft, and a material conveying device for receiving particles cut by the pelletizing blade is also installed on the machine base.

[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 pelletizer 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 pelletizer 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 and they are arranged horizontally in parallel. 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 sink cavity, the die hole plate is provided with an embedding protrusion embedded in the mounting sink cavity, a filter hole plate is installed in the mounting sink cavity, the embedding protrusion of the die hole plate is inserted into the mounting sink 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 sink cavity.

[0018] After adopting the above technical solution, the effect of the utility model is as follows: since 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 provided 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 provided at the downstream end of the extrusion barrel, an extrusion hole is provided on the die head, a mounting shaft is fixedly mounted 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, and the blades of the pelletizer blades include a blade close to The die head has an inner blade surface and an outer blade surface facing away from the die head, wherein the inner blade surface forms an inner angle with the plane of the die head, and the outer blade surface forms an outer angle with the plane of the die head, both of which are acute angles. A gap adjustment device is mounted on the mounting shaft to adjust the gap between the cutting edge of the pelletizer blade and the die head, and a material receiving and conveying device is also mounted on the base to receive the pellets cut by the pelletizer blade. Thus, in this extrusion pelletizing device, the pelletizer blade holder is directly fixed to the die head via the mounting shaft, and the pelletizer blade then adjusts the gap via the gap adjustment device to optimize the cutting gap. After the foam material is extruded through the extrusion orifice, it expands in volume. After the expansion and pelletizing, the particle-air interface increases, resulting in rapid cooling of the material. The inner angle formed between the inner blade surface and the plane of the die head allows only the cutting edge of the pelletizer blade to be close to the die head, preventing material from adhering to the inner blade surface during pelletizing. Thus, the pelletizer blade can meet the extrusion pelletizing requirements of the foam material, and the pelletized material is delivered via 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 outside 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 rest against the adjusting screw sleeve. By rotating the adjusting screw sleeve, the pelletizer seat can be axially squeezed to make the blade 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 be in contact with the adjusting screw sleeve, so that the blade is always kept at an appropriate gap, which is convenient for pelletizing without sticking.

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

[0021] Furthermore, since a central raised plane is provided on the plane of the die head, the extrusion hole is located within the range of the central raised plane, which can reduce the contact area between the blade and the die head plane and avoid wear of the blade.

[0022] Furthermore, the material receiving and conveying device includes a receiving hopper fixed to the machine base, the receiving hopper is located below the pelletizer seat, a cover covering the pelletizer seat and pelletizer blade is provided on the receiving hopper, a discharge pipe is connected to the bottom of the receiving hopper, the discharge pipe is connected to 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. The neck cross-sectional area of ​​the closing pipe section body is half the cross-sectional area of ​​the discharge pipe. Therefore, the material receiving and conveying device uses the fan to blow the material out of the discharge pipe, and the closing pipe section is provided upstream to increase the flow rate of the airflow, thereby quickly carrying away the particles and avoiding accumulation. 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 will be further described below with reference to the accompanying drawings and embodiments.

[0025] Figure 1 It is a structural schematic diagram of an embodiment of the utility model;

[0026] Figure 2 This is a structural diagram of another angle of the embodiment of the utility model;

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

[0028] Figure 4 It is a structural schematic diagram of the pelletizing part of an embodiment of the utility model;

[0029] Figure 5 yes Figure 4 Right view;

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

[0031] Figure 7 This is a structural diagram of a pelletizer holder according to an embodiment of the present invention;

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

[0033] Figure 9 This is a schematic structural diagram of the extrusion screw of an embodiment of the utility model;

[0034] In the figure: 1. Machine 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. Pelletizer holder; 8. Pelletizer holder drive device; 9. Screw drive device; 10. Pelletizer blade; 101. Inner blade surface; 102. Outer blade surface; 103. Connecting part; 104. Set screw; 11. Adjusting screw sleeve; 12. Compression spring; 13. Central raised platform; 14. Receiving hopper; 15. Cover; 16. Discharge pipe; 17. Discharge fan; 18. End pipe section; 181. Upstream connecting flange; 182. Downstream connecting flange; 183. End pipe section body; 19. Die head fixing plate; 20. Die hole plate; 21. Mounting sink cavity; 22. Embedded protrusion; 23. Filter hole plate; 24. Extrusion hole. DETAILED DESCRIPTION

[0035] The present invention will be described in further detail below through specific embodiments.

[0036] like Figure 1-9As shown, an extrusion and pelletizing device for foaming materials includes 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 provided 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 provided at the downstream end of the extrusion barrel 2, an extrusion hole 24 is provided on the die head, a mounting shaft 6 is fixedly provided on the die head, a pelletizer seat 7 is rotatably mounted on the mounting shaft 6, a knife seat driving device 8 for driving the pelletizer seat 7 to rotate is installed on the machine base 1, and a pelletizer seat 7 is fixedly mounted on the pelletizer seat 7. Several pelletizer blades 10 are provided, each of which has a cutting edge covering the extrusion hole 24 of the die head. The cutting edge of the pelletizer blade 10 includes an inner blade surface 101 close to the die head and an outer blade surface 102 away from the die head. The inner blade surface 101 forms an inner angle with the plane of the die head, and the outer blade surface 102 forms an outer angle with the plane of the die head. Both the inner angle and the outer angle are acute angles. In this embodiment, the inner angle is set to 10-20°. Of course, the inner angle can also be set to other angles as needed. There are four pelletizer blades 10, which are evenly distributed around the pelletizer base 7. A gap adjustment device for adjusting the gap between the blade of the pelletizer blade 10 and the die head is installed on the mounting shaft 6. The machine base 1 is also equipped with a material conveying device for receiving the particles cut by the pelletizer blade 10.

[0037] In this embodiment, the die head includes a die head fixing plate 19 and a die orifice plate 20. The inner blade surface 101 and the die orifice plate 20 form the aforementioned inner angle, and the outer blade surface 102 and the die orifice plate 20 form the aforementioned outer angle. The die head fixing plate 19 is fixed to the downstream end of the extruder barrel 2 by bolts. The downstream end of the die head fixing plate 19 is provided with a mounting cavity 21. The die orifice plate 20 is provided with an embedding protrusion 22 embedded in the mounting cavity 21. A filter plate 23 is installed in the mounting cavity 21. The embedding protrusion 22 of the die orifice plate 20 is inserted into the mounting cavity 21 and fixed to the die head fixing plate 19 by bolts. The extrusion hole 24 is provided on the die orifice plate 20 and communicates with the inner cavity of the extruder barrel 2 through the mounting cavity 21. Among them, the die orifice 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 outside the pelletizer seat 7. A compression spring 12 is mounted on the mounting shaft 6. The elastic force of the compression spring 12 forces the pelletizer seat 7 to rest against the adjusting screw sleeve 11.

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

[0040] The blade holder drive device 8 includes a blade holder drive motor. A pulley is provided on the pelletizer blade holder 7. The blade holder drive motor drives the pelletizer blade holder 7 to rotate via the pulley. The pelletizer blade holder 7 is provided with a first bearing mounting hole and a second bearing mounting hole. A first bearing is loosely mounted in the first bearing mounting hole, while a 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 races of the first and second bearings are mounted on the mounting shaft 6. A compression spring 12 has one end pressing against the first bearing and the other end pressing against the second bearing. The pelletizer blade holder 7 is provided with several mounting surfaces. The connecting portion 103 is secured to each mounting surface via at least two fixing screws 104. The pelletizer blade 10 comprises a blade body and a connecting portion 103. The blade body is provided with the aforementioned inner and outer cutting edges 101, 102. The connecting portion 103 is provided with an axial adjustment slot. A fixing screw 104 is installed in the axial adjustment slot. The fixing screw 104 secures the connecting portion 103 to the pelletizer blade holder 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. The neck cross-sectional area of ​​the closing pipe section body 183 is half 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. A groove 35 is provided on the spiral blade of the mixing section 34, and 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 portion 103 is adjusted to a suitable fixed position. The elastic force of the compression spring 12 forces the pelletizer seat 7 to rest against the adjusting screw sleeve 11. Rotating the adjusting screw sleeve 11 axially squeezes the pelletizer seat 7 so that the blade is close to the die plate 20, thereby reducing the gap. When the gap needs to be enlarged, the adjustment 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 always maintains an appropriate gap, optimizing the gap during the cutting process. During operation, the screw drive device 9 drives the extrusion screw 3 to rotate, and the knife seat drive device 8 drives the pelletizer seat 7 to rotate through the pulley. The feeding device 4 feeds the material, 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 area 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 pelletizer 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 pelletizer 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 air circuit system, actuators such as servo motors, gear transmission mechanisms, and lead screw and nut mechanisms mentioned in this embodiment are all current conventional technologies. The specific structures and principles and other designs of the 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 existing technology 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 in detail the vacuum components, gas circuits, and program control, indicating that the air circuit structure in this embodiment is also 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 air 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 in the claims of the present invention.

Claims

1. A foaming material extrusion and pelletizing device, comprising a base, an extrusion barrel fixedly mounted on the base, an extrusion screw rotatably mounted in the extrusion barrel, a feeding device and a foaming agent adding device provided on the extrusion barrel, and a screw drive device for driving the extrusion screw to rotate mounted on the 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 knife seat is rotatably mounted on the mounting shaft, a knife seat driving device for driving the pelletizer knife seat to rotate is installed on the machine base, a plurality of pelletizer blades are fixedly mounted on the pelletizer knife 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 conveying device for receiving particles cut by the pelletizer blade is also installed on the machine base.

2. The extrusion and pelletizing device for 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 mounted 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 foamed material according to claim 2, wherein: The pelletizing blade includes a blade body and a connecting portion, the blade body is provided with the cutting 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 pelletizing blade seat.

4. The extrusion and pelletizing device for foaming material according to claim 3, characterized in that: 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.

5. The extrusion and pelletizing device for foaming material 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, and a cover is provided on the material receiving hopper to cover 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.

6. The extrusion and pelletizing device for foaming material 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 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. 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 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.

9. The foam material extrusion and pelletizing device 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 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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