An underwater pelletizer for plastic granulation

Abstract

The utility model belongs to the technical field of granulator, especially underwater granulator for plastics granulation, including base, plastic extruder and cooling box, the base is fixedly installed with plastic extruder, the feeding inlet of plastic extruder is fixed with feeding hopper above, the cooling box is equipped with cutting cutter head that corresponds with extrusion port position cooperation, cutting cutter head one end is connected with drive motor, cooling pipe and circulating pipe are installed on the cooling box respectively, pump body is installed on cooling pipe and circulating pipe, the end of cooling pipe is connected with shower head, and heat exchanger is installed on circulating pipe, the cutting and preliminary cooling process of this application are all completed in the water medium of cooling box instantaneously, and the water environment effectively isolates air, completely avoids the high temperature oxidation and yellowing phenomenon on the surface of particle, and the melt is cut and cooled and shaped quickly under water instantaneously, and the particle is not easy to deform.

Description

Technical Field

[0001] This utility model belongs to the field of pelletizer technology, specifically relating to an underwater pelletizer for plastic pelletizing. Background Technology

[0002] Plastic pelleting is a process of processing plastic raw materials into granular products. It is achieved through steps such as heating and plasticizing, and extrusion molding. It involves raw material processing, temperature control and equipment operation. Plastic pelleting mainly includes four core steps: raw material processing, melt plasticizing, extrusion molding and pelletizing.

[0003] In the field of plastics processing, pelletizing is a crucial step in forming molten plastic into regular pellets for subsequent molding. Currently, the most common pelletizing methods in existing technologies are carried out in air. This involves the molten plastic being extruded from a die, first cooled by air cooling or water traction, and then cut in the air by a rotating cutter. This "air pelletizing" method has some inherent technical problems:

[0004] Because the cutting process is directly exposed to the air, the high-temperature plastic melt cross-section is very likely to react with oxygen in the air, causing oxidation and yellowing of the granule surface, which affects the appearance and quality of the product. At the same time, the freshly cut granules still have a high residual temperature, and they are prone to sticking together during the collection process, forming "double granules" or "multiple granules", resulting in poor granule uniformity and requiring subsequent screening, which adds to the process. To address this, we propose an underwater pelletizer for plastic pelletizing. Utility Model Content

[0005] To address the issues raised in the background art, where the cutting process involves direct exposure to air, the high-temperature plastic melt surface readily reacts with oxygen, leading to oxidation and yellowing of the granules, affecting product appearance and quality. Furthermore, the freshly cut granules retain a high residual temperature, making them prone to sticking together during collection, forming "double granules" or "multiple granules," resulting in poor granule uniformity and requiring subsequent screening, thus adding processing steps, this invention provides an underwater plastic pelletizer.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an underwater pelletizer for plastic granulation, comprising a base, a plastic extruder, and a cooling box. The plastic extruder is fixedly installed on the base, a feed hopper is fixed above the feed end of the plastic extruder, an extrusion tube is fixed at the discharge end of the plastic extruder, and a drive mechanism is connected to one end of the plastic extruder.

[0007] The extrusion tube is bolted to the end of an extrusion port, and a cooling box is provided outside the extrusion port. The cooling box contains a cutting disc that corresponds to the position of the extrusion port. One end of the cutting disc is connected to a drive motor. Cooling pipes and circulation pipes are installed on the cooling box. Pumps are installed on both the cooling pipes and the circulation pipes. A spray head is connected to the end of the cooling pipes. A heat exchanger is installed on the circulation pipes.

[0008] As a preferred embodiment of the underwater pelletizer for plastic pelletizing according to this utility model, the driving mechanism is a combination of a variable frequency motor and a reducer.

[0009] In a preferred embodiment of the present invention, an underwater pelletizer for plastic pelletizing is provided, wherein the extrusion port is a porous template and the extrusion port is fixed to the end of the extrusion tube by bolts.

[0010] As a preferred embodiment of the underwater pelletizer for plastic pelletizing according to this utility model, the rotating blade of the cutting disc is in close contact with or maintains a small gap with the end face of the extrusion port.

[0011] As a preferred embodiment of the underwater pelletizer for plastic pelletizing according to this utility model, a spray head is installed on the top of the cooling box, and the cooling box is connected to the spray head through the cooling pipe and the pump body.

[0012] As a preferred embodiment of the underwater pelletizer for plastic granulation of this utility model, a liquid storage tank is fixedly installed on one side of the cooling box, the heat exchanger is a plate heat exchanger, and the cooling box is connected to the liquid storage tank through the pump body, the circulation pipe, and the heat exchanger.

[0013] As a preferred embodiment of the underwater pelletizer for plastic granulation of this utility model, a filter box is detachably installed at the bottom of the cooling box, and the bottom of the filter box has a hollow mesh structure.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows: In this application, the cutting and initial cooling processes are completed instantly in the water medium of the cooling tank. The water environment effectively isolates the air, completely avoiding high-temperature oxidation and yellowing of the particle surface. The melt is instantly cut and rapidly cooled and shaped underwater, making the particles less prone to deformation. At the same time, the water flow causes the particles to cool and solidify rapidly, completely eliminating the risk of particles sticking together, ensuring the independence and high regularity of the particles, significantly improving product quality, and preventing the cutting process from being directly exposed to the air, which is prone to reacting with oxygen in the air at high temperatures, and the problem that freshly cut particles are prone to sticking together during collection. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0017] Figure 2 This is a schematic diagram of the left-side structure of this utility model;

[0018] Figure 3 This is a schematic diagram of the internal structure of the present invention;

[0019] Figure 4 This is a schematic diagram of the external structure of this utility model.

[0020] In the diagram: 1. Base; 2. Plastic extruder; 3. Feed hopper; 4. Drive mechanism; 5. Extrusion tube; 6. Cooling box; 7. Liquid storage tank; 8. Cooling pipe; 9. Pump body; 10. Circulation pipe; 11. Heat exchanger; 12. Spray head; 13. Drive motor; 14. Cutting disc; 15. Extrusion port; 16. Filter box. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] Example 1

[0023] like Figures 1-4 As shown;

[0024] An underwater pelletizer for plastic granulation includes a base 1, a plastic extruder 2, and a cooling box 6. The plastic extruder 2 is fixedly installed on the base 1. A feed hopper 3 is fixed above the feed end of the plastic extruder 2. An extrusion pipe 5 is fixed at the discharge end of the plastic extruder 2. One end of the plastic extruder 2 is connected to a drive mechanism 4. An extrusion port 15 is bolted to the end of the extrusion pipe 5. The cooling box 6 is covered by a cooling pipe 15. A cutting disc 14 corresponding to the position of the extrusion port 15 is provided inside the cooling box 6. One end of the cutting disc 14 is connected to a drive motor 13. Cooling pipes 8 and circulation pipes 10 are respectively installed on the cooling box 6. Pump bodies 9 are installed on both cooling pipes 8 and circulation pipes 10. A spray head 12 is connected to the end of the cooling pipe 8. A heat exchanger 11 is installed on the circulation pipe 10.

[0025] In this implementation plan: The cutting and initial cooling processes of this application are completed instantly in the water medium of the cooling box 6. The water environment effectively isolates the air, completely avoiding high-temperature oxidation and yellowing on the particle surface. The melt is instantly cut and rapidly cooled and shaped underwater, making the particles less prone to deformation. At the same time, the water flow causes the particles to cool and solidify rapidly, completely eliminating the risk of particles sticking together, ensuring the independence and high regularity of the particles, and significantly improving product quality.

[0026] In an optional embodiment, the drive mechanism 4 is a combination of a variable frequency motor and a reducer.

[0027] In this implementation scheme, a combination of a variable frequency motor and a reducer is used as the drive mechanism 4. Its advantage is that it can precisely control and steplessly adjust the speed of the extruder screw, which allows the equipment to flexibly adapt to the specific requirements of different types of plastics such as PE, PP, and ABS for processing temperature and shear force, thereby optimizing the plasticizing effect.

[0028] In an optional embodiment, the extrusion port 15 is a porous template, and the extrusion port 15 is fixed to the end of the extrusion tube 5 by bolts.

[0029] In this implementation plan, the extrusion port 15 adopts a porous template structure, which has the advantage of being able to extrude multiple plastic melt strips at one time, greatly improving the production efficiency of a single machine.

[0030] In an alternative embodiment, the rotating cutting edge of the cutting disc 14 is in close contact with or maintains a small gap with the end face of the extrusion port 15.

[0031] In this implementation scheme: the structure ensures that the cutting edge of the cutting disc 14 and the end face of the extrusion port 15 form a precise fit, which can cleanly and neatly cut the extruded melt strip instead of pulling or impacting it. This directly ensures that the produced plastic granules have a flat, smooth, burr-free cut surface and a regular and uniform shape.

[0032] In an optional embodiment, a spray head 12 is installed on the top of the cooling box 6, and the cooling box 6 is connected to the spray head 12 through the cooling pipe 8 and the pump body 9.

[0033] In this implementation plan, a top spray head 12 is set up to form an independent spray circuit. Its beneficial effect is that it can actively and uniformly spray and cool the high-temperature particles that have just been cut, achieving secondary enhanced cooling. It can instantly remove a large amount of heat from the particles, allowing them to quickly solidify and set, and completely avoid the problem of mutual adhesion or deformation that may occur when high-temperature particles are in water due to short residence time.

[0034] In an optional embodiment, a liquid storage tank 7 is fixedly installed on one side of the cooling tank 6, and the heat exchanger 11 is a plate heat exchanger. The cooling tank 6 is connected to the liquid storage tank 7 through the pump body 9, the circulation pipe 10, and the heat exchanger 11.

[0035] In this implementation plan: The closed-loop circulating cooling system is designed to achieve efficient recovery and recycling of cooling water, with extremely high water resource utilization, energy saving and environmental protection. The plate heat exchanger, due to its high heat exchange efficiency and compact structure, can quickly and efficiently cool the hot water drawn from the cooling tank 6 to the temperature required by the process, thereby continuously and stably providing low-temperature cooling water to the system and ensuring a constant and reliable cooling effect throughout the pelletizing process.

[0036] In an optional embodiment, a filter box 16 is detachably installed inside the lower part of the cooling box 6, and the bottom of the filter box 16 has a perforated mesh structure.

[0037] In this implementation plan: a detachable filter box 16 is provided to collect the cut plastic particles. After the water in the cooling box 6 is extracted, the plastic particles will fall naturally into the box. After the water in the box is filtered out, the plastic particles can be obtained.

[0038] Working principle:

[0039] Plastic raw materials are fed into the plastic extruder 2 through the feed hopper 3. The plastic extruder 2 is powered by the drive mechanism 4 at its end. The drive mechanism 4 consists of a high-power, variable frequency speed-regulating motor and a reducer, which drives the screw inside the extruder to rotate, thereby realizing the conveying, compression, melting, and homogenization of the material. The resulting high-temperature plastic melt is pushed by the screw and finally extruded in strip form from the extrusion port 15 through the extrusion tube 5. The plastic extruder 2 is existing technology equipment, and its detailed working principle will not be described again.

[0040] The extruded molten strip immediately enters the cooling tank 6 filled with cooling water. The drive motor 13 is started, and the drive motor 13 drives the cutting disc 14 to rotate at high speed. The blade of the cutting disc 14 is in close contact with the end face of the extrusion port 15 or with a very small gap. The rotating blade instantly cuts the molten strip extruded in the water to form high-temperature plastic granules.

[0041] The high-temperature particles generated during cutting immediately fall into the water in the cooling tank 6, and then into the filter tank 16. At the same time, the spray head 12 installed at the top of the cooling tank 6 sprays low-temperature cooling water downwards. This cooling water is pumped out from the storage tank 7 by the pump body 9 and transported to the spray head 12 through the cooling pipe 8. The spray water flow not only further accelerates the cooling and solidification of the particles and prevents them from sticking together, but also plays a role in disturbing the water flow and transporting the particles. The particles cool and solidify rapidly in the water, forming a final product with a smooth surface and uniform size.

[0042] The high-temperature cooling water that has absorbed heat gathers at the bottom of the cooling tank 6. Another pump 9 draws this water out of the cooling tank 6 through the circulation pipe 10. Driven by the pump, it is forced to flow through the heat exchanger 11. Inside the heat exchanger 11, the drawn water exchanges heat efficiently with the external refrigerant, such as chilled water, and its temperature drops rapidly to the set range. The cooled water is then transported back to the storage tank 7 for temporary storage, thus completing a complete cycle. This ensures that the cooling water supplied to the spray head 12 is always at a constant low temperature, guaranteeing a continuous and stable cooling effect.

[0043] The filter box 16 is connected to the cooling box 6 via a slide rail. After pelletizing, the filter box 16 is pulled out of the cooling box 6, and the water is filtered out through the filter screen at the bottom of the filter box 16 to obtain plastic pellets.

[0044] Finally, it should be noted that the above are merely preferred embodiments of this utility model and are not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An underwater pelletizer for plastic granulation, comprising a base (1), a plastic extruder (2), and a cooling tank (6), characterized in that: A plastic extruder (2) is fixedly installed on the base (1). A feed hopper (3) is fixed above the feed end of the plastic extruder (2). An extrusion tube (5) is fixed at the discharge end of the plastic extruder (2). One end of the plastic extruder (2) is connected to a drive mechanism (4). The end of the extrusion tube (5) is bolted with an extrusion port (15). The extrusion port (15) is covered with a cooling box (6). The cooling box (6) is equipped with a cutting disc (14) that corresponds to the position of the extrusion port (15). One end of the cutting disc (14) is connected to a drive motor (13). The cooling box (6) is equipped with a cooling pipe (8) and a circulation pipe (10). Both the cooling pipe (8) and the circulation pipe (10) are equipped with pump bodies (9). The end of the cooling pipe (8) is connected to a spray head (12). The circulation pipe (10) is equipped with a heat exchanger (11).

2. The underwater pelletizer for plastic pelletizing according to claim 1, characterized in that: The drive mechanism (4) is a combination of a variable frequency motor and a reducer.

3. The underwater pelletizer for plastic pelletizing according to claim 1, characterized in that: The extrusion port (15) is a porous template, and the extrusion port (15) is fixed to the end of the extrusion tube (5) by bolts.

4. The underwater pelletizer for plastic pelletizing according to claim 1, characterized in that: The rotating blade of the cutting disc (14) is in close contact with or maintains a small gap with the end face of the extrusion port (15).

5. The underwater pelletizer for plastic pelletizing according to claim 1, characterized in that: A spray head (12) is installed on the top of the cooling box (6), and the cooling box (6) is connected to the spray head (12) through the cooling pipe (8) and the pump body (9).

6. The underwater pelletizer for plastic pelletizing according to claim 1, characterized in that: A liquid storage tank (7) is fixedly installed on one side of the cooling tank (6). The heat exchanger (11) is a plate heat exchanger. The cooling tank (6) is connected to the liquid storage tank (7) through the pump body (9), the circulation pipe (10), and the heat exchanger (11).

7. The underwater pelletizer for plastic pelletizing according to claim 1, characterized in that: A filter box (16) is detachably installed inside the lower part of the cooling box (6), and the bottom of the filter box (16) has a hollowed-out mesh structure.

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