Underwater particle cutting device with pressure regulating function for foamed particle production

Abstract

The invention belongs to the field of polylactic acid foamed particle production equipment, and particularly relates to an underwater granulating device with a pressure regulating function for foamed particle production, which comprises a water tank, a mounting sleeve is arranged at the left end of the water tank, a valve seat and a die head are mounted in the mounting sleeve, and a linear feeding section, a contraction section and an external expansion section are sequentially arranged in the valve seat from left to right; a plurality of discharging holes are formed in the die head in a penetrating mode, an installation hole and a guide hole which are distributed in a left-right mode are formed between the left end and the right end of the die head in a penetrating mode, a material guiding body is installed in the installation hole, a guide shaft is arranged in a center hole of the material guiding body in a sliding fit mode, the left end of the guide shaft is connected with a valve element, the right end of the guide shaft extends into the guide hole, and a positioning table located in the installation hole is fixedly connected to the guide shaft. The guide shaft is sleeved with a pressure adjusting spring located between the positioning table and the die head. The discharging pressure of the die head can be automatically adjusted to be in a proper range all the time, so that the geometric dimensions of cut foaming particles are uniform and consistent, and the forming quality of products is effectively guaranteed.

Description

Technical Field

[0001] The invention relates to an underwater pelletizing device for foaming particle production with a pressure regulating function, belonging to the field of polylactic acid foaming particle production equipment. Background Art

[0002] Due to their environmental friendliness, biodegradability, and cushioning properties, polylactic acid (PLA) foam particles are widely used in packaging, 3D printing, and medical materials. During the production process, the molten material extruded from the extruder is cut and shaped using a pelletizer. Due to the high viscosity of the molten PLA foam particles, traditional pelletizing methods are prone to clumping and sticking to the blade. Underwater pelletizing, which uses a water-assisted cutting medium, effectively reduces the risk of material sticking and ensures production continuity. Furthermore, underwater pelletizing allows for controlled particle shape and size while achieving rapid cooling and solidification, ensuring product quality. Therefore, underwater pelletizing is commonly used in the production of polylactic acid (PLA) foam particles.

[0003] For example, Chinese utility model patent CN214293911U discloses an energy-saving underwater pelletizer for EVA pellets. While this prior art can achieve underwater pelletizing of foamed particles, it suffers from the following drawbacks: Because the feed pipe is a simple straight tube without a pressure regulator, abnormal melt pressure can lead to unstable discharge from the dispensing tray, resulting in uneven geometric dimensions of the cut foamed particles, affecting product quality. Summary of the Invention

[0004] In view of the above deficiencies in the prior art, the present invention aims to solve the technical problem of providing an underwater pelletizing device for foamed particle production with a pressure regulating function that can automatically adjust the die discharge pressure.

[0005] The underwater pelletizing device for producing foamed particles with a pressure regulating function of the present invention comprises a base, a knife seat and a motor are installed on the base, the left end of the knife seat is fixedly connected to a water tank, the water tank is provided with a water inlet and a water outlet, a rotating shaft connected to the motor is rotatably connected in the knife seat, the rotating shaft is fixedly connected to the knife seat located in the water tank, and a cutter is installed on the knife seat, wherein a mounting sleeve is provided at the left end of the water tank, a valve seat and a die head are installed in the mounting sleeve, a linear feed section, a contraction section and an expansion section are sequentially provided in the valve seat from left to right, and a through hole is provided on the die head. There are several discharge holes, one end of the discharge hole corresponds to the outward expansion section, and the other end of the discharge hole corresponds to the cutter. There are mounting holes and guide holes distributed on the left and right between the left and right ends of the die head. A guide body corresponding to the outward expansion section is installed in the mounting hole, and a guide shaft is slidably adapted in the center hole of the guide body. The left end of the guide shaft is connected to a valve core corresponding to the contraction section, and the right end of the guide shaft extends into the guide hole. The guide shaft is fixedly connected to a positioning platform located in the mounting hole, and the guide shaft is sleeved with a pressure-adjusting spring located between the positioning platform and the die head.

[0006] Furthermore, the water inlet is fixedly connected to a guide plate with a cross-section in the water tank, and a through hole corresponding to the knife seat is passed through the guide plate.

[0007] Furthermore, a support block is fixedly connected between the back side of the guide plate and the inner side wall of the water inlet.

[0008] Furthermore, the die head is placed in a mounting sleeve, the valve seat and the mounting sleeve are threadedly connected, and a pressure ring is connected between the valve seat and the die head.

[0009] Furthermore, the discharge hole includes a long hole feed section, a transition section and a short hole discharge section, which are arranged in sequence from left to right, and the aperture of the long hole feed section is larger than the aperture of the short hole discharge section.

[0010] Furthermore, the left end of the valve core is conical.

[0011] Furthermore, the material guide body is threadedly connected to the mounting hole.

[0012] Furthermore, the positioning platform is slidably fitted with the mounting hole.

[0013] Furthermore, the guide shaft and the guide hole are slidably fitted together.

[0014] Working principle and process:

[0015] When in use, water enters the water tank through the water inlet and is discharged through the water outlet. The motor starts to drive the cutter to rotate through the rotating shaft and the cutter seat. The molten material extruded by the extruder enters the valve seat through the linear feed section, then enters the expansion section through the gap between the contraction section and the valve core, and enters the various discharge holes under the action of the material guide body. The molten material flowing out of the discharge hole is then cut into particles by the rotating cutter. Then, the cut particles are discharged through the water outlet with the water flow to the next process.

[0016] During normal operation, the melt pressure output by the extruder and the elastic force of the pressure-regulating spring are in a balanced state. At this time, the gap between the contraction section and the valve core tends to be stable, so the discharge hole can stably output the melt material.

[0017] When the pressure of the melt material output by the extruder increases, the melt material will push the valve core to overcome the elastic force of the pressure regulating spring and move to the right, thereby reducing the gap between the contraction section and the valve core, thereby generating a pressure drop and reducing the pressure of the melt material delivered to the discharge hole;

[0018] When the pressure of the melt material output by the extruder decreases, the pressure-regulating spring pushes the positioning table to the left, thereby driving the valve core to move to the left through the guide shaft, so that the gap between the contraction section and the valve core becomes larger, thereby generating a pressurization effect, and increasing the pressure of the melt material delivered to the discharge hole.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The underwater pelletizing device for producing foamed particles with a pressure regulating function of the present invention can automatically adjust the discharge pressure of the die head so that it is always within an appropriate range, thereby making the geometric dimensions of the cut foamed particles uniform and effectively ensuring the molding quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention;

[0022] Figure 2 yes Figure 1 Enlarged view of the M in the middle;

[0023] Figure 3 yes Figure 1 Enlarged view of point N in the middle.

[0024] In the figure: 1. Base; 2. Motor; 3. Knife holder; 4. Water tank; 5. Rotating shaft; 6. Knife holder; 7. Discharge hole; 8. Material guide body; 9. Guide shaft; 10. Linear feed section; 11. Valve seat; 12. Outward expansion section; 13. Die head; 14. Cutter; 15. Mounting sleeve; 16. Guide plate; 17. Water outlet; 18. Water inlet; 19. Support block; 20. Valve core; 21. Contraction section; 22. Pressure ring; 23. Long hole feed section; 24. Transition section; 25. Short hole discharge section; 26. Mounting hole; 27. Positioning platform; 28. Pressure regulating spring; 29. ​​Guide hole; 30. Through hole. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are further described below with reference to the accompanying drawings:

[0026] Example 1:

[0027] like Figures 1 to 3 As shown, the underwater pelletizing device for producing foamed particles with a pressure regulating function of the present invention comprises a base 1, a knife seat 3 and a motor 2 are installed on the base 1, the left end of the knife seat 3 is fixedly connected to a water tank 4, the water tank 4 is provided with a water inlet 18 and a water outlet 17, a rotating shaft 5 connected to the motor 2 is rotatably connected in the knife seat 3, a knife seat 6 located in the water tank 4 is fixedly connected on the rotating shaft 5, a cutter 14 is installed on the knife seat 6, wherein the left end of the water tank 4 is provided with a mounting sleeve 15, a valve seat 11 and a die head 13 are installed in the mounting sleeve 15, a linear feed section 10, a contraction section 21 and an expansion section 12 are sequentially provided in the valve seat 11 from left to right, and a die head 13 is provided on the die head 13. There are several discharge holes 7 running through it, one end of the discharge hole 7 corresponds to the outward expansion section 12, and the other end of the discharge hole 7 corresponds to the cutter 14. The left and right ends of the die head 13 are passed through with mounting holes 26 and guide holes 29 distributed on the left and right. A guide body 8 corresponding to the outward expansion section 12 is installed in the mounting hole 26, and a guide shaft 9 is slidably adapted in the center hole of the guide body 8. The left end of the guide shaft 9 is connected to the valve core 20 corresponding to the contraction section 21, and the right end of the guide shaft 9 extends into the guide hole 29. A positioning platform 27 located in the mounting hole 26 is fixedly connected to the guide shaft 9, and a pressure-regulating spring 28 located between the positioning platform 27 and the die head 13 is sleeved on the guide shaft 9.

[0028] During use, water enters the water tank 4 through the water inlet 18 and is discharged through the water outlet 17. The motor 2 is activated, driving the cutter 14 to rotate via the rotating shaft 5 and the cutter seat 6. The molten material extruded by the extruder enters the valve seat 11 through the linear feed section 10, then enters the expansion section 12 through the gap between the contraction section 21 and the valve core 20, and enters the discharge holes 7 under the action of the material guide body 8. The molten material flowing out of the discharge holes 7 is then cut into particles by the rotating cutter 14. The cut particles are then discharged through the water outlet 17 along with the water flow to the next process.

[0029] During normal operation, the melt pressure output by the extruder and the elastic force of the pressure regulating spring 28 are in a balanced state. At this time, the gap between the contraction section 21 and the valve core 20 tends to be stable, so the discharge hole 7 can stably output the melt material.

[0030] When the pressure of the melt output by the extruder increases, the melt pushes the valve core 20 to overcome the elastic force of the pressure-regulating spring 28 and move to the right, thereby reducing the gap between the contraction section 21 and the valve core 20, thereby generating a pressure drop and reducing the pressure of the melt delivered to the discharge port 7;

[0031] When the pressure of the melt material output by the extruder decreases, the pressure-regulating spring 28 can push the positioning platform 27 to move to the left, thereby driving the valve core 20 to move to the left through the guide shaft 9, so that the gap between the contraction section 21 and the valve core 20 becomes larger, thereby generating a pressurization effect, and increasing the pressure of the melt material delivered to the discharge hole 7.

[0032] Example 2:

[0033] like Figures 1 to 3 As shown, based on Example 1,

[0034] Furthermore, a deflector plate 16 with a cross-section shaped like an "X" is fixedly connected to the water inlet 18 and corresponding to the water tank 4. A through-hole 30 corresponding to the blade holder 6 is formed through the deflector plate 16. This creates a convergence-divergence flow path between the water inlet 18, the deflector plate 16, the die head 13, and the water outlet 17. Due to the Venturi effect, a high-speed shearing water flow is generated at the cutter 14, allowing the cut foam particles to flow quickly with the water through the water outlet 17, effectively preventing the cut particles from sticking together and ensuring the quality of the product.

[0035] Furthermore, a support block 19 is fixedly connected between the back side of the guide plate 16 and the inner side wall of the water inlet 18. Since the guide plate 16 is located in the contraction section at the water inlet 18, the water pressure is relatively high, and the support block 19 can effectively improve the stability of the guide plate 16.

[0036] Furthermore, the die head 13 is placed within the mounting sleeve 15, and the valve seat 11 and the mounting sleeve 15 are threadedly connected. A pressure ring 22 is connected between the valve seat 11 and the die head 13. By screwing the valve seat 11 into the mounting sleeve 15, the pressure ring 22 can compress the die head 13 within the mounting sleeve 15. The provision of the pressure ring 22 prevents wear of the die head 13 and provides protection. The die head 13 can be removed by disassembling the valve seat 11, thereby facilitating maintenance and replacement of the die head 13.

[0037] Furthermore, the discharge hole 7 includes a long hole feed section 23, a transition section 24, and a short hole discharge section 25. These three sections are arranged sequentially from left to right, with the long hole feed section 23 having a larger aperture than the short hole discharge section 25. The discharge hole 7 employs a large inlet and a small outlet, effectively reducing pressure at the discharge end and thereby improving the stability of the discharge pressure. This further enhances particle size uniformity and ensures product quality.

[0038] Furthermore, the left end of the valve core 20 is conical, which can guide the melt material input from the extruder to facilitate the melt material to flow into the contraction section 21.

[0039] Furthermore, the material guide body 8 is threadedly connected to the mounting hole 26. The material guide body 8 can be disassembled to facilitate maintenance of the material guide body 8, the pressure regulating spring 28 and other components.

[0040] Furthermore, the sliding fit between the positioning platform 27 and the mounting hole 26 can further improve the operating stability of the guide shaft 9.

[0041] Furthermore, the guide shaft 9 and the guide hole 29 are slidably fitted together, which can further improve the operational stability of the guide shaft 9 .

[0042] It is particularly noted that in the description of the present invention, the directions or positional relationships indicated by the terms "left" and "right" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than requiring the present invention to be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

Claims

1. An underwater pelletizing device for producing foamed particles with a pressure regulating function, comprising a base (1), a knife seat (3) and a motor (2) mounted on the base (1), a water tank (4) fixedly connected to the left end of the knife seat (3), a water inlet (18) and a water outlet (17) provided on the water tank (4), a rotating shaft (5) connected to the motor (2) rotatably connected in the knife seat (3), a knife seat (6) located in the water tank (4) fixedly connected to the rotating shaft (5), a cutting knife (14) mounted on the knife seat (6), characterized in that: The left end of the water tank (4) is provided with a mounting sleeve (15), a valve seat (11) and a die head (13) are installed in the mounting sleeve (15), a linear feed section (10), a contraction section (21) and an expansion section (12) are provided in the valve seat (11) from left to right, a plurality of discharge holes (7) are passed through the die head (13), one end of the discharge hole (7) corresponds to the expansion section (12), and the other end of the discharge hole (7) corresponds to the cutter (14), and the left and right ends of the die head (13) are passed through with mounting holes (26) and guide holes distributed on the left and right. A guide body (8) adapted to the expansion section (12) is installed in the mounting hole (26), a guide shaft (9) is slidably adapted in the center hole of the guide body (8), the left end of the guide shaft (9) is connected to a valve core (20) adapted to the contraction section (21), the right end of the guide shaft (9) extends into the guide hole (29), a positioning platform (27) located in the mounting hole (26) is fixedly connected to the guide shaft (9), and a pressure regulating spring (28) located between the positioning platform (27) and the die head (13) is sleeved on the guide shaft (9).

2. The underwater pelletizing device with pressure regulating function for foamed particle production according to claim 1, characterized in that: The water inlet (18) is fixedly connected to a guide plate (16) with a cross-section in the shape of a Chinese character "X" in correspondence with the water tank (4). A through hole (30) corresponding to the knife seat (6) is passed through the guide plate (16).

3. The underwater pelletizing device for producing foamed particles with a pressure regulating function according to claim 2, characterized in that: A support block (19) is fixedly connected between the back side of the guide plate (16) and the inner side wall of the water inlet (18).

4. The underwater pelletizing device with pressure regulating function for producing foamed particles according to claim 1, characterized in that: The die head (13) is placed in the mounting sleeve (15), the valve seat (11) and the mounting sleeve (15) are threadedly connected, and a pressure ring (22) is connected between the valve seat (11) and the die head (13).

5. The underwater pelletizing device for producing foamed particles with a pressure regulating function according to claim 1, characterized in that: The discharge hole (7) comprises a long hole feed section (23), a transition section (24) and a short hole discharge section (25), wherein the long hole feed section (23), the transition section (24) and the short hole discharge section (25) are arranged in sequence from left to right, and the aperture of the long hole feed section (23) is larger than the aperture of the short hole discharge section (25).

6. The underwater pelletizing device with pressure regulating function for producing foamed particles according to claim 1, characterized in that: The left end of the valve core (20) is conical.

7. The underwater pelletizing device with pressure regulating function for foamed particle production according to claim 1, characterized in that: The material guide body (8) is threadedly connected to the mounting hole (26).

8. The underwater pelletizing device with pressure regulating function for producing foamed particles according to any one of claims 1 to 7, characterized in that: The positioning platform (27) is slidably fitted with the mounting hole (26).

9. The underwater pelletizing device with pressure regulating function for foamed particle production according to claim 8, characterized in that: The guide shaft (9) and the guide hole (29) are slidably fitted together.

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