Screw extruder for plasticizing plastic particles

Abstract

The invention provides a screw extruder for plasticizing plastic particles, which belongs to the technical field of plastic regeneration extrusion equipment and comprises a base, a driving unit, a charging barrel and a screw. Wherein the charging barrel is provided with a plurality of fixing pipes in the axial direction, piston pipes capable of sliding in the radial direction of the screw rod are arranged in the fixing pipes, telescopic holes corresponding to the piston pipes are formed in the charging barrel, and shearing grooves corresponding to the piston pipes are formed in the screw rod; and an air pressure cavity is formed in the end, away from the screw rod, of the fixing pipe. The piston pipe capable of extending into the screw pitch of the screw rod is arranged on the charging barrel, air pressure control is utilized, the pressure is increased, the piston pipe extends into the screw pitch of the screw rod, plastic is sheared along with rotation of the screw rod, the piston pipe can improve the radial shearing effect of the plastic in the conveying process, and plasticization of the plastic is more uniform.

Description

Technical Field

[0001] This invention belongs to the technical field of plastic recycling extrusion equipment, specifically referring to a screw extruder for plasticizing plastic granules. Background Technology

[0002] Recycled plastic pellets are environmentally friendly plastic raw materials produced through waste plastic recycling processes. They are created through crushing, washing, and granulation, achieving the resource-based regeneration of waste plastics. The screw extruder, as the core molding equipment in the recycled plastic pelleting process, uses the screw's spiral conveying, shearing, plasticizing, and extrusion molding actions to process molten waste plastic raw materials into uniformly sized and stable recycled plastic pellets. Its plasticizing effect, extrusion precision, and operational stability directly determine the key properties of recycled plastic pellets, such as appearance, density, and melt flow index. It is a crucial piece of equipment for ensuring the quality of recycled plastic pellet products and improving pelleting production efficiency and raw material utilization.

[0003] At present, screw extruders mainly achieve the shearing and plasticizing of plastic granules by setting different screw pitches in different sections of the screw. However, since the screw pitch is fixed, the corresponding degree of shearing and plasticizing is also fixed. When processing plastic raw materials with different physical properties, or when the raw materials need to be sheared and plasticized to different degrees, it is necessary to replace the screw with the corresponding specification, which is time-consuming and labor-intensive. Summary of the Invention

[0004] In view of the above situation and to overcome the defects of the prior art, the purpose of the present invention is to provide a screw extruder for plasticizing plastic granules, so as to at least partially solve the problems mentioned in the background art.

[0005] The technical solution adopted by this invention is as follows: This invention proposes a screw extruder for plasticizing plastic granules, comprising: The base has a drive unit mounted on one end; A material cylinder is mounted on the drive unit and is arranged coaxially with the output shaft of the drive unit. A screw is located inside the barrel, and one end of the screw is connected to the output shaft of the drive unit; The material cylinder is provided with a plurality of fixed tubes along the axial direction, and a piston tube that can slide radially along the screw is provided inside the fixed tube; The barrel is provided with a telescopic hole corresponding to the piston tube, and the screw is provided with a shearing groove corresponding to the piston tube, so that the piston tube can slide into the pitch of the screw. A pressure chamber is provided at the end of the fixed tube away from the screw. The pressure chamber is configured such that when the pressure increases, the piston tube can be pushed into the barrel.

[0006] Furthermore, a spring is provided inside the fixed tube, and the spring is configured to apply a thrust to the piston tube that slides into the fixed tube.

[0007] Furthermore, the piston tube is provided with multiple side holes, and a side rod is slidably disposed in the side holes; A sliding tube is provided inside the piston tube. An air bladder is sleeved at one end of the sliding tube inside the piston tube. One end of the side rod is connected to the air bladder. The air bladder is configured to inflate and push the side rod to slide outward from the piston tube.

[0008] Furthermore, a first connecting pipe is fixed to the fixed pipe, one end of the first connecting pipe is connected to the air pressure chamber, and the other end of the first connecting pipe is connected to an external air supply device.

[0009] Furthermore, a second connecting pipe is fixed on the fixed pipe, one end of the sliding pipe extends to the outside of the piston pipe and is slidably connected to the inside of the second connecting pipe, and the second connecting pipe is connected to an external air supply device.

[0010] Furthermore, the sliding tube is provided with an air hole in the area corresponding to the airbag, and the air hole allows the sliding tube to communicate with the airbag.

[0011] Furthermore, a first air supply pipe and a second air supply pipe are provided on the outside of the material cylinder. Multiple first connecting pipes are connected to the first air supply pipe and connected to an external air supply device through the first air supply pipe. Multiple second connecting pipes are connected to the second air supply pipe and connected to an external air supply device through the second air supply pipe.

[0012] Furthermore, a feeding unit is provided above one end of the material cylinder near the drive unit, and the discharge end of the feeding unit is connected to the interior of the material cylinder.

[0013] Furthermore, the material cylinder is provided with multiple heating units along the axial direction, and the heating units are wrapped around the outside of the material cylinder.

[0014] Furthermore, a protective cover is fitted over the outside of the heating unit.

[0015] Beneficial effects: 1. By installing a piston tube on the barrel that can extend into the screw pitch and using air pressure control, the piston tube extends into the screw pitch by increasing the air pressure. As the screw rotates, it shears the plastic. The piston tube can improve the radial shearing effect of the plastic during the conveying process, making the plasticization of the plastic more uniform.

[0016] 2. By setting a telescopic side rod on the piston tube and using an expandable / contractable air bladder for control, the side rod can be pushed outward by the inflation of the air bladder, so that the side rod extends to the outside of the piston tube. At this time, the extended side rod is also within the pitch of the screw, which can further improve the radial shear effect of the plastic during the conveying process and make the plasticization of the plastic more uniform. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a screw extruder for plasticizing plastic granules according to an embodiment of the present invention; Figure 2 This is a schematic diagram showing the installation position of the heating unit in a screw extruder for plasticizing plastic granules, according to an embodiment of the present invention. Figure 3 This is a schematic diagram showing the positional distribution of the first and second air supply pipes in a screw extruder for plasticizing plastic granules, as proposed in an embodiment of the present invention. Figure 4 This is a schematic diagram showing the position distribution of the fixed tube in a screw extruder for plasticizing plastic granules, as proposed in an embodiment of the present invention. Figure 5 This is a schematic diagram of a screw extruder for plasticizing plastic granules, in which both the piston tube and the side rod are in a contracted state, according to an embodiment of the present invention. Figure 6 This is a schematic diagram of a screw extruder for plasticizing plastic granules, in which both the piston tube and the side rod are extended, according to an embodiment of the present invention. Figure 7 This is a schematic diagram showing the location of air pores in a screw extruder for plasticizing plastic granules, as proposed in an embodiment of the present invention.

[0018] The components are as follows: 1. Base; 2. Drive unit; 3. Material cylinder; 301. Telescopic hole; 31. Feeding unit; 32. Heating unit; 33. Protective cover; 4. Screw; 401. Shearing groove; 5. Fixing tube; 501. Air pressure chamber; 502. Side hole; 51. Piston tube; 52. Spring; 53. Sliding tube; 531. Air hole; 54. Airbag; 55. Side rod; 511. First connecting tube; 512. Second connecting tube; 6. First air supply tube; 7. Second air supply tube.

[0019] The accompanying drawings are provided to further understand the embodiments and form part of the specification. They are used together with the embodiments for explanation and do not constitute a limitation on the embodiments. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection.

[0021] In the description of the embodiments, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments.

[0022] Combination Figure 1 As shown, an embodiment of the present invention provides a screw extruder for plasticizing plastic granules, including a base 1, a drive unit 2, a barrel 3 and a screw 4.

[0023] The drive unit 2 is installed at one end of the base 1. The drive unit 2 includes a drive motor and a reducer. The output shaft of the drive motor is connected to the input shaft of the reducer. After the drive motor is reduced in speed and torque is increased by the reducer, it drives the screw 4 to rotate.

[0024] Furthermore, the screw 4 is located inside the barrel 3, and the barrel 3 and the screw 4 are arranged coaxially. By rotating the screw 4, the plastic particles in the barrel 3 are pushed from one end to the other end.

[0025] In a specific embodiment, one end of the barrel 3 is fixed to the output shaft of the reducer of the drive unit 2 and is arranged coaxially with the output shaft of the drive unit 2, so that one end of the screw 4 can be coaxially connected to the output shaft of the reducer and the output shaft of the reducer drives the screw 4 to rotate.

[0026] Combination Figure 1 and Figure 2 As shown, a feeding unit 31 is provided above one end of the material cylinder 3 near the drive unit 2. The discharge end of the feeding unit 31 is connected to the inside of the material cylinder 3. Plastic granules are first added into the feeding unit 31, and then the feeding unit 31 feeds the material into the material cylinder 3.

[0027] It is understandable that the drive unit 2 drives the screw 4 to rotate so that the screw 4 can transport the plastic particles in the barrel 3 from one end near the feeding unit 31 to the other end.

[0028] In a specific embodiment, the feeding unit 31 includes a hopper and a valve. Plastic granules are first added into the hopper, the valve is opened, and the plastic granules can fall into the material cylinder 3 by gravity. When the valve is closed, the feeding stops.

[0029] In an optional embodiment, a screw feeder can be installed at the bottom of the hopper. By rotating the screw feeder, material can be fed into the cylinder 3 at a uniform speed. By controlling the rotation speed of the screw feeder, the speed of feeding material into the cylinder 3 can be precisely controlled.

[0030] Combination Figure 2 and Figure 3 As shown, the barrel 3 is provided with multiple heating units 32 along the axial direction. The heating units 32 are wrapped around the outside of the barrel 3. The plastic particles inside the barrel 3 are heated by the heating units 32 and, together with the extrusion and shearing of the screw 4, the plastic particles are plasticized. By installing the corresponding mold on the barrel 3, the plasticized plastic is re-extruded as the screw 4 continues to push.

[0031] Furthermore, a protective cover 33 is provided on the outside of the heating unit 32. The protective cover 33 serves to protect the heating unit 32, prevent the heating unit 32 from being damaged by external impact, and prevent personnel from accidentally touching it and causing burns.

[0032] In a specific embodiment, the heating unit 32 uses resistance wire heating. The resistance wire heater is wrapped around the outside of the material cylinder 3. Current passes through the resistance wire to generate heat, and the heat is conducted to the material cylinder 3 to plasticize the plastic particles.

[0033] In an optional embodiment, the heating unit 32 may also be an electromagnetic eddy current heater, in which the induction coil is wrapped around the outside of the barrel 3 and controlled by an external controller. The electromagnetic eddy current can quickly heat the barrel 3, and the temperature regulation speed is relatively fast.

[0034] Combination Figure 3 , Figure 4 and Figure 5 As shown, the barrel 3 is provided with a plurality of fixed tubes 5 along the axial direction. A piston tube 51 that can slide radially along the screw 4 is provided inside the fixed tube 5. The barrel 3 is provided with a telescopic hole 301 corresponding to the piston tube 51, so that the piston tube 51 can extend into the interior of the barrel 3 through the telescopic hole 301.

[0035] Furthermore, the screw 4 is provided with a shear groove 401 corresponding to the piston tube 51. The shear groove 401 allows the piston tube 51 to slide into the pitch of the screw 4. When the screw 4 rotates, the piston tube 51 is located in the shear groove 401 and will not interfere with the rotation of the screw 4.

[0036] Thus, when the screw 4 rotates and pushes the plastic in the barrel 3, the radial shearing effect of the plastic during the conveying process can be improved by sliding the piston tube 51 into the pitch of the screw 4, making the plasticization of the plastic more uniform.

[0037] In a specific embodiment, a pressure chamber 501 is provided at the end of the fixed tube 5 away from the screw 4. A first connecting tube 511 is fixed on the fixed tube 5. One end of the first connecting tube 511 is connected to the pressure chamber 501, and the other end of the first connecting tube 511 is connected to an external air supply device. The external air supply device can supply gas into the pressure chamber 501 through the first connecting tube 511, and can also discharge gas from the pressure chamber 501 through the first connecting tube 511. When the air pressure in the pressure chamber 501 increases, the piston tube 51 can be pushed into the material cylinder 3.

[0038] Furthermore, a spring 52 is provided inside the fixed tube 5, and the spring 52 is configured to apply a thrust to the piston tube 51 to slide into the fixed tube 5.

[0039] Thus, when it is necessary to push the piston tube 51 into the material cylinder 3, the external air supply device supplies air to the air pressure chamber 501 through the first connecting pipe 511, increasing the air pressure in the air pressure chamber 501. When the air pressure in the air pressure chamber 501 is sufficient to push the piston tube 51 and compress the spring 52, the piston tube 51 slides into the material cylinder 3 and compresses the spring 52, putting it into a state of stored force (e.g., Figure 6 As shown), at this time, the extended piston tube 51 can improve the radial shear effect of the plastic during the conveying process, making the plasticization of the plastic more uniform. When it is not necessary to enhance the shear effect, the gas in the air pressure chamber 501 is discharged, causing the air pressure in the air pressure chamber 501 to decrease. Under the action of the spring 52, the piston tube 51 is pushed and retracted into the fixed tube 5 (as shown). Figure 5 (As shown).

[0040] In a specific embodiment, an annular gap is provided between the piston tube 51 and the fixed tube 5 for mounting the spring 52, and the spring 52 is located within the annular gap (e.g., Figure 5 , 6 (As shown).

[0041] It should be noted that the end of the piston tube 51 facing the air pressure chamber 501 is in a sliding seal with the inner wall of the fixed tube 5 to ensure the air pressure chamber 501 is airtight.

[0042] Combination Figure 5 and Figure 6As shown, the piston tube 51 is provided with multiple side holes 502, and a side rod 55 is slidably arranged in the side holes 502. A sliding tube 53 is provided in the piston tube 51, and an air bladder 54 is sleeved on one end of the sliding tube 53 inside the piston tube 51. One end of the side rod 55 is connected to the air bladder 54. When the air bladder 54 is inflated, it can push the side rod 55 outward, so that the side rod 55 extends to the outside of the piston tube 51. When the air bladder 54 is contracted, the side rod 55 is pulled and completely retracted into the side hole 502.

[0043] Furthermore, the side rod 55 is arranged perpendicular to the axial direction of the piston tube 51, so that when the air bladder 54 inflates, the side rod 55 can extend along the axial direction perpendicular to the piston tube 51 (e.g., Figure 6 (As shown).

[0044] In a specific embodiment, a second connecting pipe 512 is fixed on the fixed pipe 5, and one end of the sliding pipe 53 extends to the outside of the piston pipe 51 and is slidably connected to the inside of the second connecting pipe 512. The second connecting pipe 512 is connected to an external air supply device. When the piston pipe 51 moves, the sliding pipe 53 and the second connecting pipe 512 are always in a connected state.

[0045] The external air supply device inflates the airbag 54 through the second connecting pipe 512 and the sliding pipe 53, causing the airbag 54 to expand. Correspondingly, it can also vent air through the second connecting pipe 512 and the sliding pipe 53, causing the airbag 54 to contract.

[0046] Thus, when it is necessary to push the piston tube 51 into the material cylinder 3, the external air supply device supplies air to the air pressure chamber 501 through the first connecting pipe 511, increasing the air pressure in the air pressure chamber 501. When the air pressure in the air pressure chamber 501 is sufficient to push the piston tube 51 and compress the spring 52, the piston tube 51 slides into the material cylinder 3 and compresses the spring 52, putting it into a state of stored force (e.g., Figure 6 (as shown) After the piston tube 51 is fully extended, the external air supply device inflates the air bag 54 through the second connecting pipe 512 and the sliding pipe 53. After the air bag 54 is inflated, it can push the side rod 55 outward, so that the side rod 55 extends to the outside of the piston tube 51. At this time, the extended piston tube 51 and side rod 55 can improve the radial shear effect of the plastic during the conveying process, making the plasticization of the plastic more uniform.

[0047] When enhanced shearing effect is not required, the gas inside the airbag 54 is first discharged, causing the airbag 54 to fully contract. The side rod 55 is pulled and fully retracted into the side hole 502. At this time, the side rod 55 will not interfere with the sliding of the piston tube 51. Then, the gas in the pressure chamber 501 is discharged, reducing the air pressure in the pressure chamber 501. Under the action of the spring 52, the piston tube 51 is pushed and retracted into the fixed tube 5 (e.g., Figure 5 (As shown).

[0048] Combination Figure 7 As shown, the area corresponding to the sliding tube 53 and the airbag 54 is provided with an air hole 531. The air hole 531 connects the sliding tube 53 and the airbag 54, and air is supplied to the airbag 54 through the air hole 531. Correspondingly, the air in the airbag 54 is discharged through the air hole 531.

[0049] Combination Figure 3 and Figure 4 As shown, a first air supply pipe 6 and a second air supply pipe 7 are provided on the outside of the material cylinder 3. Multiple first connecting pipes 511 are connected to the first air supply pipe 6 and connected to an external air supply device through the first air supply pipe 6. The external air supply device simultaneously fills and releases air into multiple air pressure chambers 501 through the first air supply pipe 6.

[0050] Multiple second connecting pipes 512 are connected to the second air supply pipe 7 and connected to an external air supply device through the second air supply pipe 7. The external air supply device simultaneously inflates and deflates multiple airbags 54 through the second air supply pipe 7.

[0051] The working principle of this invention is as follows: When it is necessary to push the piston tube 51 into the material cylinder 3, the external air supply device supplies air to the air pressure chamber 501 through the first connecting pipe 511, increasing the air pressure in the air pressure chamber 501. When the air pressure in the air pressure chamber 501 is sufficient to push the piston tube 51 and compress the spring 52, the piston tube 51 slides into the material cylinder 3 and compresses the spring 52, putting it into a state of stored force (e.g., Figure 6 (as shown) After the piston tube 51 is fully extended, the external air supply device inflates the air bag 54 through the second connecting pipe 512 and the sliding pipe 53. After the air bag 54 is inflated, it can push the side rod 55 outward, so that the side rod 55 extends to the outside of the piston tube 51. At this time, the extended piston tube 51 and the side rod 55 are within the pitch of the screw 4, which can improve the radial shear effect of the plastic during the conveying process and make the plastic more uniform.

[0052] When enhanced shearing effect is not required, the gas inside the airbag 54 is first discharged, causing the airbag 54 to fully contract. The side rod 55 is pulled and fully retracted into the side hole 502. At this time, the side rod 55 will not interfere with the sliding of the piston tube 51. Then, the gas in the pressure chamber 501 is discharged, reducing the air pressure in the pressure chamber 501. Under the action of the spring 52, the piston tube 51 is pushed and retracted into the fixed tube 5 (e.g., Figure 5 (As shown).

[0053] In summary, by providing a piston tube 51 on the barrel 3 that can extend into the pitch of the screw 4, and by using air pressure control, increasing the air pressure allows the piston tube 51 to extend into the pitch of the screw 4. As the screw 4 rotates and shears the plastic, the piston tube 51 can improve the radial shearing effect of the plastic during the conveying process, making the plasticization of the plastic more uniform.

[0054] By setting a telescopic side rod 55 on the piston tube 51 and controlling it with an expandable / contractable air bladder 54, the side rod 55 can be pushed outward by the inflation of the air bladder 54, so that the side rod 55 extends to the outside of the piston tube 51. At this time, the extended side rod 55 is also within the pitch of the screw 4, which can further improve the radial shear effect of the plastic during the conveying process and make the plasticization more uniform.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0056] The embodiments have been described above, and such description is not restrictive. The figures shown are only one embodiment, and the actual structure is not limited to this. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the inventive spirit, such design should fall within the scope of protection.

Claims

1. A screw extruder for plasticizing plastic granules, characterized in that, include: A base (1) with a drive unit (2) installed at one end; The material cylinder (3) is mounted on the drive unit (2) and is arranged coaxially with the output shaft of the drive unit (2); The screw (4) is located inside the barrel (3), and one end of the screw (4) is connected to the output shaft of the drive unit (2); The material cylinder (3) is provided with a plurality of fixed tubes (5) along the axial direction, and a piston tube (51) that can slide radially along the screw (4) is provided inside the fixed tube (5). The barrel (3) is provided with a telescopic hole (301) corresponding to the piston tube (51), and the screw (4) is provided with a shear groove (401) corresponding to the piston tube (51), so that the piston tube (51) can slide into the pitch of the screw (4). The fixed tube (5) is provided with a pressure chamber (501) at one end away from the screw (4). The pressure chamber (501) is configured such that when the pressure increases, the piston tube (51) can be pushed into the material cylinder (3).

2. The screw extruder for plasticizing plastic granules according to claim 1, characterized in that: A spring (52) is provided inside the fixed tube (5), and the spring (52) is configured to apply a thrust to the piston tube (51) to slide into the fixed tube (5).

3. The screw extruder for plasticizing plastic granules according to claim 1, characterized in that: The piston tube (51) is provided with a plurality of side holes (502), and a side rod (55) is slidably disposed in the side holes (502); A sliding tube (53) is provided inside the piston tube (51). An air bladder (54) is sleeved at one end of the sliding tube (53) inside the piston tube (51). One end of the side rod (55) is connected to the air bladder (54). The air bladder (54) is configured to inflate and push the side rod (55) to slide outward from the piston tube (51).

4. The screw extruder for plasticizing plastic granules according to claim 1, characterized in that: A first connecting pipe (511) is fixed on the fixed pipe (5). One end of the first connecting pipe (511) is connected to the air pressure chamber (501), and the other end of the first connecting pipe (511) is connected to an external air supply device.

5. The screw extruder for plasticizing plastic granules according to claim 3, characterized in that: A second connecting pipe (512) is fixed on the fixed pipe (5). One end of the sliding pipe (53) extends to the outside of the piston pipe (51) and is slidably connected to the inside of the second connecting pipe (512). The second connecting pipe (512) is connected to an external gas supply device.

6. The screw extruder for plasticizing plastic granules according to claim 3, characterized in that: The sliding tube (53) is provided with an air hole (531) in the area corresponding to the airbag (54), and the air hole (531) allows the sliding tube (53) to communicate with the airbag (54).

7. The screw extruder for plasticizing plastic pellets according to any one of claims 4 or 5, characterized in that: The outer side of the material cylinder (3) is provided with a first air supply pipe (6) and a second air supply pipe (7). Multiple first connecting pipes (511) are connected to the first air supply pipe (6) and connected to an external air supply device through the first air supply pipe (6). Multiple second connecting pipes (512) are connected to the second air supply pipe (7) and connected to an external air supply device through the second air supply pipe (7).

8. The screw extruder for plasticizing plastic granules according to claim 1, characterized in that: A feeding unit (31) is provided above one end of the material cylinder (3) near the drive unit (2), and the discharge end of the feeding unit (31) is connected to the inside of the material cylinder (3).

9. The screw extruder for plasticizing plastic granules according to claim 1, characterized in that: The material cylinder (3) is provided with a plurality of heating units (32) along the axial direction, and the heating units (32) are wrapped around the outside of the material cylinder (3).

10. The screw extruder for plasticizing plastic granules according to claim 9, characterized in that: The heating unit (32) is fitted with a protective cover (33) on its outer side.

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