Plastic screw granulator and granulation process

Abstract

The application discloses a plastic screw granulator and a granulation process, and relates to the technical field of plastic waste recycling, wherein the granulator comprises a granulation assembly and a rounding assembly; the granulation assembly comprises a shielding cover; the rounding assembly is arranged in the shielding cover; the rounding assembly comprises an outer cylinder, a discharging hole, a second motor, an inner cylinder and a spiral plate; the outer cylinder is provided with the discharging hole on the surface; the output end of the second motor is arranged below the outer cylinder; the second motor is used for driving the outer cylinder to rotate; the discharging hole is used for discharging the rounded particles; the qualified particles can be discharged, the yield and quality are greatly improved, and the size of the particles is prevented from being reduced due to continuous grinding. The breaking of the particles in the collision is avoided, and the defective products and waste are avoided. The loss of the finished particles is reduced, and the output rate of the final qualified products is directly improved; the movement path of the particles is guided, the rounding efficiency is improved, and the spiral plate forcibly defines the movement track of the particles, so that the particles must ascend along the spiral direction.

Description

Technical Field

[0001] This invention relates to the field of plastic waste recycling technology, and in particular to a plastic screw granulator and granulation process. Background Technology

[0002] Large quantities of waste plastic are disposed of through landfills and incineration, which not only occupies valuable land resources but may also release harmful substances that pollute soil and water sources, posing a serious threat to the ecological environment. Plastic recycling, on the other hand, is an environmentally friendly practice that uses specific recycling processes to recycle and reuse waste plastics, turning waste into valuable resources.

[0003] Waste plastic recycling methods mainly include physical recycling, chemical recycling, and energy recovery. Among them, physical recycling, which converts waste plastic into reusable plastic pellets through melting and re-granulation, has attracted much attention due to its relatively low cost and simple process. However, traditional physical recycling equipment faces challenges such as low pelletizing efficiency and unstable pellet quality when processing waste plastics with complex compositions and diverse forms.

[0004] When waste plastics are transformed into plastic pellets, these pellets typically come in various shapes. Non-spherical pellets exacerbate equipment wear during conveying and melting, causing scratches on the surfaces of screws, barrels, and molds. Simultaneously, irregular shapes increase filling resistance, requiring higher extrusion pressures or temperatures, thus increasing energy consumption and production costs. In the modification or coloring of recycled plastics, non-spherical pellets, due to differences in density and surface area, are difficult to mix thoroughly with additives or other resins, leading to performance fluctuations.

[0005] In a traditional closed-circuit spherical cylinder, all granules, regardless of whether they have reached the target roundness, must complete the entire spherical process together before being ejected from the top. Granules that have reached the standard continue to collide and rub unfinished granules and the cylinder walls unnecessarily within the cylinder; granules that have reached the standard may be further ground, becoming smaller, and break during collisions, producing fine powder and reducing the yield of the final product; furthermore, plastic granules falling into the spherical cylinder collide with each other during rotation, exhibiting an irregular upward rotational path, which reduces the spherical effect. Summary of the Invention

[0006] This application provides a plastic screw granulator and granulation process, solving the problem in the prior art where all granules, regardless of whether they have reached the target roundness, must complete the entire rounding process together before being ejected from the top. Standard granules continue to collide and rub unfinished granules and the bowl wall inside the cylinder; standard granules may be further ground, becoming smaller, and break during collisions, producing fine powder and reducing the yield of the final product; furthermore, plastic granules falling into the rolling cylinder collide with each other during rotation, exhibiting an irregular upward rotation path, leading to a reduction in rounding effect. This invention achieves immediate discharge of qualified granules, significantly improving yield and quality, and avoiding further grinding that leads to smaller size. It avoids breakage during collisions, preventing the production of defective products and waste. It reduces the loss of finished granules, directly increasing the output rate of the final qualified product; it guides the movement path of the granules, improving rounding efficiency, and the spiral plate forcibly defines the movement trajectory of the granules, requiring them to rise in the spiral direction. It ensures that each granule undergoes a sufficiently long and controllable rounding path, guaranteeing the consistency and reliability of the rounding effect. Compared to random collisions and tumbling, orderly spiral ascent concentrates energy in the rounding process rather than in disordered collisions, thus improving the rounding efficiency.

[0007] This application provides a plastic screw granulator, including a granulation component and a rounding component. The granulation component includes a shield, and the rounding component is disposed inside the shield. The rounding component includes an outer cylinder, a feeding hole, a motor, an inner cylinder, and a spiral plate. A feeding hole is opened on the surface of the outer cylinder, and the output end of motor 2 is located at the bottom of the outer cylinder. Motor 2 is used to drive the outer cylinder to rotate. The feed hole is used to pass through pre-rounded particles; The outer ring of the spiral plate is fixed inside the outer cylinder, and the inner cylinder is fixed inside the spiral plate. The spiral plate, inner cylinder, and outer cylinder form a spiral channel; Spiral plates are used to restrict the rotation direction of particles, causing them to spiral upwards and become round along the spiral direction of the spiral plate.

[0008] As an improvement, the upper part of the outer cylinder is provided with multiple feeding holes, and the cross-section of the feeding holes is circular. Multiple discharge holes are arranged in a spiral shape, and the discharge holes are located on the side of the spiral channel formed by the spiral plate, inner cylinder and outer cylinder; The diameter of the feeding hole is 1.2 times the diameter of the plastic granules after rounding, and the feeding hole is set at an angle.

[0009] As an improvement, the outer cylinder has the same shape as the inner cylinder; The outer cylinder is an inverted frustum shape that runs through its axis. The axis of the outer cylinder is on the same straight line as the axis of the inner cylinder, and the axis of the outer cylinder is perpendicular to the ground. The spiral plate is spiral-shaped, and the central axis of the spiral plate is on the same straight line as the axis of the outer cylinder.

[0010] As an improvement, the rolling assembly also includes a rotating plate, which is cylindrical in shape. The axis of the rotating plate is on the same straight line as the axis of the outer cylinder. The rotating plate is fixed to the lower end of the outer cylinder, and the output end of the motor is fixed to the lower side of the rotating plate. A gap is left between the rotating plate and the lower end of the inner cylinder, and the gap between the rotating plate and the inner cylinder is twice the diameter of the particles after rounding. The axis of motor 2 is parallel to the axis of the rotating plate, and the output end of motor 2 is fixed eccentrically to the rotating plate; Motor 2 is used to drive the rotating plate to rotate eccentrically, and the lower end of the spiral plate is fixed on the rotating plate.

[0011] As an improvement, the pelletizing assembly also includes a support platform, a screw extruder, a feeding component, an insulation component, a cooling component, a mounting port, and a mounting plate; The screw extruder is fixed on the support platform, the feeder is fixed on the screw extruder, and the output end of the feeder is connected to the screw extruder. The feeder is used to store the plastic to be formed, and the screw extruder is used to convey and extrude the plastic to be formed. The insulation component and the cooling component are fixed on the screw extruder. The insulation component is located between the feeding component and the cooling component. The insulation component is used to keep the molten plastic to be formed in the heat, and the cooling component is used to pre-cool the plastic to be formed. The shield is a rectangular parallelepiped with an opening at the bottom, and a rubber plate is fixed to the inner wall of the shield. An installation port is opened on one side of the shield, the output end of the screw extruder is fixed inside the installation port, the mounting plate is fixed at the lower opening of the shield, and the second motor is fixed on the mounting plate.

[0012] As an improvement, the pelletizing assembly also includes a cutting component, which includes a motor, a rotating block, blades, and a pelletizing hopper; Motor 1 is fixed on the side of the shield away from the installation port, and motor 1 is fixed on the shield by a rubber plate passing through the inner wall of the shield. A rotating block is fixed at the output end of the motor. There are multiple blades, which are evenly distributed in a ring on the outer ring of the rotating block. The blades are in close contact with the output end of the screw extruder. The blade is used to cut the plastic to be shaped; The material hopper is an inverted quadrangular truncated pyramid that runs vertically through the top and bottom. The four sides of the material hopper are fixed to the four sides of the inner wall of the shield. The material hopper is located below the output end of the screw extruder. The hopper is used to collect the cut particles; The lower opening of the material hopper is located directly above the inner ring of the inner cylinder; When the second motor drives the rotating plate to rotate eccentrically, the inner ring of the inner cylinder is always located directly below the material hopper.

[0013] As an improvement, the rounding assembly also includes an airbag and an air pump; The airbag is fixed to the upper side of the spiral plate, the air pump is fixed to the outside of the outer cylinder, and the output end of the air pump is connected to the airbag. The airbag is used to expand and change the spacing between the spiral plates. A conductive slip ring is fixed at the output end of the motor. The conductive slip ring is used to connect the power supply and the air pump to provide power for starting the air pump.

[0014] As an improvement, there are multiple airbags and air pumps, and they correspond one-to-one; Multiple airbags are fixed in a spiral shape on the side of the spiral plate, and the multiple airbags are interconnected.

[0015] As an improvement, the particles are rounded to a spherical shape, and the volume formula is: ; Where D is the diameter of the target particle; Mass formula: ; in, Density of plastic; Feed hole diameter: ; Where K is the feed hole diameter coefficient and D is the target particle diameter; Multi-airbag wave surface enhancement rounding, surface waveform function: ; Where h(x) is the normal height of the spiral plate at the axial position x of the spiral channel, h is the reference radial height of the surface, A is the amplitude of the radial height change caused by the expansion of the airbag, sin is the sine trigonometric function, x is the axial distance along the spiral channel, and λ is the wavelength of the waveform, i.e. the length of a complete cycle. Particle collision frequency estimation: ; Where f is the collision frequency between the particle and the waveform surface. Let λ be the average linear velocity of the particle moving along the channel, and λ be the wavelength of the waveform. Changes in particle kinetic energy: ; Where ΔE is the kinetic energy lost in each collision, and m is the particle mass. denoted as σ, where σ is the normal velocity of the particle relative to the surface instant before the collision, and e is the coefficient of restitution (0 ≤ e ≤ 1). σ is the ratio of the relative velocity after the collision to that before the collision.

[0016] A granulation process for a plastic screw granulator includes the following steps: S1: The molten plastic is stored in the feeding part and fed evenly towards the screw extruder. The plastic entering the screw extruder is kept warm by the heat insulation part and is pre-cooled by the cooling part when it reaches the outlet. This pre-cools the temperature of the unextruded plastic so that it can quickly reach the conditions for subsequent cutting into granules. S2: The plastic extruded from the output end of the screw extruder is cut into granules by rotating the blades driven by the motor. The cut plastic granules are collected through the hopper, fall into the inner cylinder, and land on the rotating plate. S3: The outer and inner cylinders are rotated by motor two. During the rotation, due to the centrifugal force, the plastic particles enter the spiral plate and rise spirally. S4: As the plastic granules spiral upward, they gradually become round. During the rotation and rolling process, they gradually cool down and solidify. If any rounded plastic granules appear during the rolling process, they can be thrown out through the feeding hole; they can also be thrown out from the top of the spiral plate. The thrown-out granules hit the rubber plate on the inner wall of the shield and fall down for collection from the lower opening of the shield.

[0017] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: Firstly, it enables qualified particles to be shipped out immediately, significantly improving yield and quality and preventing further grinding that would reduce their size. It also avoids breakage during collisions, preventing the production of defective products and waste. This reduces the loss of finished particles, directly increasing the output rate of final qualified products. Furthermore, it guides the particle movement path, improving rounding efficiency. The spiral plate forcibly defines the particle's trajectory, requiring it to rise along the spiral direction. This ensures that each particle undergoes a sufficiently long and controllable rounding path, guaranteeing the consistency and reliability of the rounding effect. Compared to random collisions and tumbling, the ordered spiral ascent concentrates energy on rounding rather than disordered collisions, thus improving rounding efficiency. Secondly, the dynamic adjustment of the rolling channel spacing enhances the equipment's adaptability. By controlling the inflation volume of the airbags, the spacing between the spiral plates can be actively and in real time changed, making it more applicable. It also actively prevents material adhesion and channel blockage. When the airbags expand, they can squeeze and push up the material stuck to the channel wall, causing it to fall off. When they contract, they create gaps, and when they expand, they create compression. This dynamic change can effectively break the adhesion tendency of the material, achieving self-cleaning of the spiral channel, ensuring the continuity and stability of production, and avoiding the trouble of downtime for cleaning. Third, it forces plastic granules to tumble, eliminating linear slippage. The smooth spiral channel may cause some irregularly shaped granules to slip; while the wavy uneven surface formed by multiple airbags completely breaks the smoothness. During the movement, the granules will constantly collide with the protruding parts of the airbags, producing tiny jumps and forced tumbling; ensuring the rounding effect, greatly enhancing the kneading and tumbling action required for rounding, ensuring that even granules with poor initial shape can be effectively rounded. Attached Figure Description

[0018] Figure 1 This is a perspective sectional view of a plastic screw granulator according to the present invention; Figure 2 This is a perspective view of a plastic screw granulator according to the present invention; Figure 3 This is a perspective sectional view of a shielding cover for a plastic screw granulator according to the present invention; Figure 4 This is a schematic diagram of the spiral plate structure of a plastic screw granulator according to the present invention; Figure 5 This is a schematic diagram of the outer cylinder structure of a plastic screw granulator according to the present invention; Figure 6 This is a perspective sectional view of the spiral plate installation of a plastic screw granulator according to the present invention; Figure 7 This is a perspective sectional view of the inner cylinder installation of a plastic screw granulator according to the present invention; Figure 8 This is a front sectional view of the inner cylinder installation of a plastic screw granulator according to the present invention; Figure 9 This is a schematic diagram of the feeding hole opening of a plastic screw granulator according to the present invention; Figure 10 This is a schematic diagram of the airbag installation of a plastic screw granulator according to the present invention; Figure 11 This is a schematic diagram of the air pump installation for a plastic screw granulator according to the present invention. Figure 1 ; Figure 12 This is a schematic diagram of the air pump installation for a plastic screw granulator according to the present invention. Figure 2 ; Figure 13 This is a schematic diagram of the wavy air bladder of a plastic screw granulator according to the present invention.

[0019] In the diagram: 100, granulation component; 110, support platform; 120, screw extruder; 130, feeding component; 140, insulation component; 150, cooling component; 160, shield; 161, mounting port; 170, mounting plate; 180, cutting component; 181, motor one; 182, rotating block; 183, blade; 184, hopper; 200, rounding component; 210, outer cylinder; 211, feeding hole; 220, motor two; 230, inner cylinder; 240, spiral plate; 250, rotating plate; 260, air bag; 270, air pump. Detailed Implementation

[0020] To facilitate understanding of the present invention, a more complete description of this application will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the invention. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to enable a more thorough and complete understanding of the disclosure of the present invention.

[0021] It should be noted that the terms "vertical," "horizontal," "up," "down," "left," "right," and similar expressions used in this article are for illustrative purposes only and do not represent the only possible implementation.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] Example 1: As Figures 1-9 As shown, this application discloses a plastic screw granulator, including a granulation component 100 and a rounding component 200. The granulation component 100 includes a support platform 110, a screw extruder 120, a feeding component 130, a heat preservation component 140, a cooling component 150, a shield 160, a mounting port 161, a mounting plate 170, and a cutting component 180. The rounding assembly 200 is disposed inside the shield 160. The rounding assembly 200 includes an outer cylinder 210, a discharge hole 211, a second motor 220, an inner cylinder 230, a spiral plate 240, and a rotating plate 250. A feeding hole 211 is provided on the surface of the outer cylinder 210, and the output end of the second motor 220 is located under the outer cylinder 210. The second motor 220 is used to drive the outer cylinder 210 to rotate. The feed hole 211 is used to pass through the rounded particles; The upper part of the outer cylinder 210 has a discharge hole 211. There are multiple discharge holes 211, and the cross-section of the discharge hole 211 is circular. The diameter of the feeding hole 211 is 1.2 times the diameter of the plastic granules after rounding, and the feeding hole 211 is set at an angle.

[0024] Specifically, during the rotation of the plastic granules inside the outer cylinder 210, the plastic granules that have become rounded are directly thrown out through the discharge hole 211, without having to be thrown out from the top of the outer cylinder 210. This avoids the granules that have met the standards continuing to collide and rub against the unfinished granules and the bowl wall inside the bowl, which would cause them to be ground down, become smaller, break during collisions, produce fine powder, and reduce the yield of the final product. The inclined discharge hole 211 facilitates the ejection of plastic particles during the rolling process.

[0025] The outer ring of the spiral plate 240 is fixed inside the outer cylinder 210, and the inner cylinder 230 is fixed inside the spiral plate 240; A spiral channel is formed between the spiral plate 240, the inner cylinder 230, and the outer cylinder 210; The spiral plate 240 is used to limit the rotation direction of the particles, so that the particles spiral upward and roll into a round shape along the spiral direction of the spiral plate 240.

[0026] The outer cylinder 210 and the inner cylinder 230 have the same shape; The outer cylinder 210 is an inverted frustum shape that runs through its axis. The axis of the outer cylinder 210 and the axis of the inner cylinder 230 are on the same straight line. The axis of the outer cylinder 210 is perpendicular to the ground. The spiral plate 240 is spiral in shape, and the central axis of the spiral plate 240 is on the same straight line as the axis of the outer cylinder 210.

[0027] Multiple discharge holes 211 are arranged in a spiral shape, and the discharge holes 211 are located on the side of the spiral channel formed by the spiral plate 240, the inner cylinder 230, and the outer cylinder 210; The rotating plate 250 is cylindrical, and the axis of the rotating plate 250 is on the same straight line as the axis of the outer cylinder 210. The rotating plate 250 is fixed at the lower end of the outer cylinder 210, and the output end of the motor 220 is fixed on the lower side of the rotating plate 250. A gap is left between the lower end of the rotating plate 250 and the inner cylinder 230. The gap between the rotating plate 250 and the inner cylinder 230 is twice the diameter of the granules after rounding. The axis of motor 220 is parallel to the axis of rotating plate 250, and the output end of motor 220 is eccentrically fixed to rotating plate 250; Motor 220 is used to drive the rotating plate 250 to rotate eccentrically, and the lower end of the spiral plate 240 is fixed on the rotating plate 250.

[0028] Specifically, the outer cylinder 210 and the inner cylinder 230 are driven to rotate by the motor 220. During the rotation, due to the centrifugal force, the plastic particles enter the spiral plate 240 and spiral upward. As the plastic particles spiral upward, they gradually become round. The rounded particles are thrown out from the feed hole 211 or from the top of the outer cylinder 210.

[0029] The screw extruder 120 is fixed on the support platform 110, and the unloading part 130 is fixed on the screw extruder 120. The output end of the unloading part 130 is connected to the screw extruder 120. The unloading part 130 is used to store the plastic to be formed, and the screw extruder 120 is used to convey and extrude the plastic to be formed. The heat insulation component 140 and the cooling component 150 are fixed on the screw extruder 120. The heat insulation component 140 is located between the feeding component 130 and the cooling component 150. The heat insulation component 140 is used to heat the molten plastic to be formed, and the cooling component 150 is used to pre-cool the plastic to be formed. Specifically, the molten plastic is stored in the feeding unit 130 and fed evenly towards the screw extruder 120. The plastic entering the screw extruder 120 is kept warm by the heat insulation unit 140 and pre-cooled by the cooling unit 150 when it reaches the outlet.

[0030] The shield 160 is a cuboid with an opening at the bottom, and a rubber plate is fixed to the inner wall of the shield 160. Specifically, the rubber plate fixed inside the shield 160 can reduce the impact force after the plastic particles are thrown out from the outer cylinder 210, and reduce the degree of deformation.

[0031] A mounting port 161 is opened on one side of the shield 160. The output end of the screw extruder 120 is fixed in the mounting port 161. The mounting plate 170 is fixed at the lower opening of the shield 160. The motor 220 is fixed on the mounting plate 170.

[0032] The cutting component 180 includes a motor 181, a rotating block 182, a blade 183, and a hopper 184; Motor 181 is fixed on the side of shield 160 away from mounting port 161. Motor 181 passes through the rubber plate on the inner wall of shield 160 and is fixed on shield 160.

[0033] The output end of motor 181 is fixed with rotating block 182. There are multiple blades 183. The blades 183 are evenly distributed in a ring on the outer ring of rotating block 182. The blades 183 are in close contact with the output end of screw extruder 120. Blade 183 is used for cutting plastic to be shaped; The material hopper 184 is an inverted quadrangular truncated pyramid that runs vertically through the top and bottom. The four sides of the material hopper 184 are fixed to the four sides of the inner wall of the shield 160. The material hopper 184 is located below the output end of the screw extruder 120. The hopper 184 is used to collect the cut particles; Specifically, motor 181 drives blade 183 to rotate, thereby cutting the plastic granules extruded from the output end of screw extruder 120 into granules. The cut plastic granules are collected through hopper 184, fall into inner cylinder 230, and land on rotating plate 250.

[0034] The lower opening of the material hopper 184 is located directly above the inner ring of the inner cylinder 230; When motor 220 drives the rotating plate 250 to rotate eccentrically, the inner ring of the inner cylinder 230 is always located directly below the material hopper 184.

[0035] Specifically, when motor 220 drives the rotating plate 250 to rotate eccentrically, the inner ring of the inner cylinder 230 is always located directly below the material hopper 184, which can prevent unrounded plastic particles from falling outside the outer cylinder 210 during the rotation process, thus preventing the rounding operation from being performed.

[0036] The screw extruder 120, the feeding component 130, the heat preservation component 140, and the cooling component 150 are all existing technologies and will not be described in detail here.

[0037] A granulation process for a plastic screw granulator, using the above-mentioned apparatus, includes the following steps: S1: The molten plastic is stored in the feeding part 130 and fed evenly towards the screw extruder 120. The plastic entering the screw extruder 120 is kept warm by the heat preservation part 140 and is pre-cooled by the cooling part 150 when it reaches the outlet. The temperature of the unextruded plastic is reduced in advance so that it can quickly reach the conditions for subsequent cutting into granules. S2: The plastic extruded from the output end of the screw extruder 120 is cut into granules by the rotation of the blade 183 driven by the motor 181. The cut plastic granules are collected by the hopper 184 and fall into the inner cylinder 230 and onto the rotating plate 250. S3: The outer cylinder 210 and the inner cylinder 230 are rotated by the motor 220. During the rotation, due to the centrifugal force, the plastic particles enter the spiral plate 240 and spiral upward. S4: As the plastic granules spiral upward, they gradually become round. During the rotation and rolling process, they gradually cool down and solidify. If rounded plastic granules appear during the rolling process, they can be thrown out through the discharge hole 211; they can also be thrown out from the top of the spiral plate 240. The thrown-out granules hit the rubber plate on the inner wall of the shield 160 and fall and are collected from the lower opening of the shield 160.

[0038] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages: This system ensures that qualified particles are immediately output, significantly improving yield and quality and preventing further grinding that could lead to smaller dimensions. It also avoids breakage during collisions, preventing the production of defective products and waste. This reduces the loss of finished particles, directly increasing the output rate of final qualified products. By guiding the particle movement path and improving rounding efficiency, the spiral plate 240 forcibly defines the particle's trajectory, requiring it to rise along the spiral direction. This ensures that each particle undergoes a sufficiently long and controllable rounding path, guaranteeing the consistency and reliability of the rounding effect. Compared to random collisions and tumbling, the ordered spiral ascent concentrates energy on rounding rather than disordered collisions, thus improving rounding efficiency.

[0039] Example 2: In the above embodiment, softened but not completely solidified plastic granules may stick inside the spiral plate 240 during use, causing internal blockage; furthermore, the spacing between the upper and lower spiral plates 240 cannot be adjusted, reducing the usability. Therefore, improvements are made to the solution in Example 1, such as... Figures 10-11 As shown; The rounding assembly 200 also includes an airbag 260 and an air pump 270; The airbag 260 is fixed on the upper side of the spiral plate 240, and the air pump 270 is fixed outside the outer cylinder 210. The output end of the air pump 270 is connected to the airbag 260. The airbag 260 is used to expand and change the spacing between the spiral plates 240. A conductive slip ring is fixed at the output end of motor 220. The conductive slip ring is used to connect the power supply and air pump 270 to provide power for starting air pump 270.

[0040] Specifically, by expanding the airbag 260, the distance between the upper and lower spiral plates 240 is changed, and the inner diameter of the spiral channel is dynamically adjustable and controllable. When plastic particles stick together, the periodic expansion and contraction of the airbag 260 can actively break the adhesion points by resisting the plastic particles stuck to the inner wall. Furthermore, if plastic particles stick to the airbag 260, the expansion and contraction of the airbag 260 itself can pull and squeeze the stuck parts, thereby causing them to fall off.

[0041] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages: The dynamic adjustment of the rolling channel spacing enhances the equipment's adaptability. By controlling the inflation volume of the airbag 260, the spacing between the spiral plates 240 can be actively and in real time changed, making it more applicable. It actively prevents material adhesion and channel blockage. When the airbag 260 expands, it can squeeze and push up the material stuck to the channel wall, causing it to fall off. When it contracts, it creates gaps, and when it expands, it creates compression. This dynamic change can effectively break the adhesion tendency of the material, realize the self-cleaning of the spiral channel, ensure the continuity and stability of production, and avoid the trouble of downtime for cleaning.

[0042] Example 3: In the above examples, the cut plastic granules are irregularly shaped, causing them to slide linearly inside the spiral channel instead of rolling; this prevents them from being rounded. Therefore, Example 2 is improved as follows: Figures 12-13 As shown: There are multiple airbags 260 and air pumps 270, and they correspond one-to-one. Multiple airbags 260 are fixed in a spiral shape on the upper side of the spiral plate 240, and the multiple airbags 260 are interconnected.

[0043] Specifically, the airbags 260 located in the spiral channel are divided into multiple airbags along the spiral direction. The expansion of the airbags 260 at different positions can make the inner diameter of the spiral channel gradually decrease from bottom to top. Furthermore, when the particles are conveyed, the expansion of the airbags 260 can resist the plastic particles sliding close to the inner wall of the outer cylinder 210, making the upper side wavy and breaking the smooth surface. When the plastic particles collide with the wavy surface, they generate micro-jumps and tumbles, which enhances random motion, forces the particles to tumble, and avoids linear slippage.

[0044] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages: The forced tumbling of plastic granules eliminates linear slippage. While a smooth spiral channel might cause some irregularly shaped granules to slip, the wavy, uneven surface formed by multiple airbags 260 completely breaks the smoothness. During movement, the granules will continuously collide with the raised parts of the airbags 260, producing tiny jumps and forced tumbling. This ensures a rounding effect and greatly enhances the kneading and tumbling action required for rounding, ensuring that even granules with poor initial shape can be effectively rounded.

[0045] After the particles are rolled into rounds, they become spherical, and the volume formula is: ; Where D is the diameter of the target particle; Mass formula: ; in, Density of plastic; The diameter of the feed hole 211 is: ; Where K is the diameter coefficient of the feed hole 211, and D is the diameter of the target particle; Multi-airbag 260 wave-reinforced rounded surface, surface waveform function: ; Where h(x) is the normal height of the spiral plate 240 at the axial position x of the spiral channel, h is the reference radial height of the surface, A is the amplitude of the radial height change caused by the expansion of the airbag 260, sin is the sine trigonometric function, x is the axial distance along the spiral channel, and λ is the wavelength of the waveform, i.e. the length of a complete cycle. Particle collision frequency estimation: ; Where f is the collision frequency between the particle and the waveform surface. Let λ be the average linear velocity of the particle moving along the channel, and λ be the wavelength of the waveform. Changes in particle kinetic energy: ; Where ΔE is the kinetic energy lost in each collision, and m is the particle mass. denoted as σ, where σ is the normal velocity of the particle relative to the surface instant before the collision, and e is the coefficient of restitution (0 ≤ e ≤ 1). σ is the ratio of the relative velocity after the collision to that before the collision.

[0046] Specific examples: The target particle diameter D = 5 mm = 0.5 cm; The density of the plastic (polyethylene PE) is ρ = 0.94 g / cm³. The feed hole diameter coefficient K = 1.2; Reference height h = 10mm; Amplitude A = 2 mm; Axial distance x = 20mm; Wavelength λ = 20 mm; The linear velocity of the particle moving along the channel =50mm / s=0.05m / s; The normal velocity of the particle relative to the surface just before the collision is L = 0.1 m / s; The coefficient of recovery is e = 0.7.

[0047] Calculate particle volume: ; Mass formula: ; That is, each particle weighs approximately 0.0615g.

[0048] Feed hole diameter: ; The feed hole has a diameter of 6mm, with a 1mm margin to prevent clogging.

[0049] Multi-airbag 260 wave-reinforced rounded surface, surface waveform function: ; Particle collision frequency estimation: ; The frequency of the collision between the particles and the waveform surface is 2.5 Hz.

[0050] Changes in particle kinetic energy: ; The kinetic energy lost in each collision is approximately 0.157 μJ.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A plastic screw granulator, characterized in that, It includes a granulation component (100) and a rounding component (200). The granulation component (100) includes a shield (160). The rounding component (200) is disposed inside the shield (160). The rounding component (200) includes an outer cylinder (210), a discharge hole (211), a second motor (220), an inner cylinder (230), a spiral plate (240), an air bag (260), and an air pump (270). A feeding hole (211) is opened on the surface of the outer cylinder (210), and the output end of the second motor (220) is set under the outer cylinder (210). The second motor (220) is used to drive the outer cylinder (210) to rotate. The feed hole (211) is used to pass through the rounded particles; The outer ring of the spiral plate (240) is fixed inside the outer cylinder (210), and the inner cylinder (230) is fixed inside the inner ring of the spiral plate (240); A spiral channel is formed between the spiral plate (240), the inner cylinder (230), and the outer cylinder (210); The spiral plate (240) is used to limit the rotation direction of the particles, so that the particles spiral upward and roll into a round shape along the spiral direction of the spiral plate (240); The airbag (260) is fixed on the upper side of the spiral plate (240), and the air pump (270) is fixed outside the outer cylinder (210). The output end of the air pump (270) is connected to the airbag (260). The airbag (260) is used to expand and change the distance between the spiral plates (240). A conductive slip ring is fixed at the output end of motor 2 (220). The conductive slip ring is used to connect the power supply and the air pump (270) to provide power for the air pump (270) to start. The spacing between the upper and lower spiral plates (240) is changed by the expansion of the airbag (260).

2. The plastic screw granulator as described in claim 1, characterized in that, The upper part of the outer cylinder (210) is provided with a feeding hole (211). There are multiple feeding holes (211), and the cross-section of the feeding hole (211) is circular. Multiple discharge holes (211) are arranged in a spiral shape, and the discharge holes (211) are located on the side of the spiral channel formed by the spiral plate (240), the inner cylinder (230), and the outer cylinder (210); The diameter of the feeding hole (211) is 1.2 times the diameter of the plastic granules after rounding, and the feeding hole (211) is set at an angle.

3. A plastic screw granulator as described in claim 2, characterized in that, The outer cylinder (210) and the inner cylinder (230) have the same shape; The outer cylinder (210) is an inverted frustum shape that runs through its axis. The axis of the outer cylinder (210) and the axis of the inner cylinder (230) are on the same straight line. The axis of the outer cylinder (210) is perpendicular to the ground. The spiral plate (240) is spiral in shape, and the central axis of the spiral plate (240) is on the same straight line as the axis of the outer cylinder (210).

4. A plastic screw granulator as described in claim 1, characterized in that, The rolling assembly (200) also includes a rotating plate (250), which is cylindrical. The axis of the rotating plate (250) is on the same straight line as the axis of the outer cylinder (210). The rotating plate (250) is fixed at the lower end of the outer cylinder (210), and the output end of the second motor (220) is fixed on the lower side of the rotating plate (250). A gap is left between the lower end of the rotating plate (250) and the inner cylinder (230), and the gap between the rotating plate (250) and the inner cylinder (230) is twice the diameter of the particles after rounding. The axis of motor 2 (220) is parallel to the axis of the rotating plate (250), and the output end of motor 2 (220) is eccentrically fixed to the rotating plate (250); Motor 2 (220) is used to drive the rotating plate (250) to rotate eccentrically, and the lower end of the spiral plate (240) is fixed on the rotating plate (250).

5. A plastic screw granulator as described in claim 1, characterized in that, The pelletizing assembly (100) also includes a support platform (110), a screw extruder (120), a feeding component (130), an insulation component (140), a cooling component (150), a mounting port (161), and a mounting plate (170). The screw extruder (120) is fixed on the support platform (110), and the unloading part (130) is fixed on the screw extruder (120). The output end of the unloading part (130) is connected to the screw extruder (120). The unloading part (130) is used to store the plastic to be formed, and the screw extruder (120) is used to convey and extrude the plastic to be formed. The heat insulation component (140) and the cooling component (150) are fixed on the screw extruder (120). The heat insulation component (140) is located between the feeding component (130) and the cooling component (150). The heat insulation component (140) is used to heat the molten plastic to be formed, and the cooling component (150) is used to pre-cool the plastic to be formed. The shield (160) is a cuboid with an opening at the bottom, and a rubber plate is fixed to the inner wall of the shield (160); An installation port (161) is opened on one side of the shield (160), the output end of the screw extruder (120) is fixed in the installation port (161), the mounting plate (170) is fixed at the lower opening of the shield (160), and the second motor (220) is fixed on the mounting plate (170).

6. A plastic screw granulator as described in claim 5, characterized in that, The pelletizing assembly (100) also includes a cutter (180), which includes a motor (181), a rotating block (182), a blade (183), and a hopper (184). Motor 1 (181) is fixed on the side of the shield (160) away from the mounting port (161), and Motor 1 (181) is fixed on the shield (160) by passing through the rubber plate of the inner wall of the shield (160). The output end of motor 1 (181) is fixed with a rotating block (182). There are multiple blades (183). The blades (183) are evenly distributed in a ring on the outer ring of the rotating block (182). The blades (183) are close to the output end of the screw extruder (120). The blade (183) is used to cut the plastic to be shaped; The material hopper (184) is an inverted quadrangular truncated pyramid that runs vertically through the top and bottom. The four sides of the material hopper (184) are fixed to the four sides of the inner wall of the shield (160). The material hopper (184) is located below the output end of the screw extruder (120). The hopper (184) is used to collect the cut particles; The lower opening of the hopper (184) is located directly above the inner ring of the inner cylinder (230); When the second motor (220) drives the rotating plate (250) to rotate eccentrically, the inner ring of the inner cylinder (230) is always located directly below the material hopper (184).

7. A plastic screw granulator as described in claim 1, characterized in that, There are multiple airbags (260) and air pumps (270), and they correspond one-to-one; Multiple airbags (260) are fixed in a spiral shape on the upper side of the spiral plate (240), and the multiple airbags (260) are interconnected.

8. A plastic screw granulator as described in claim 7, characterized in that, After the particles are rolled into rounds, they become spherical, and the volume formula is: ； Where D is the diameter of the target particle; Mass formula: ； in, Density of plastic; Diameter of feed hole (211): ； Where K is the diameter coefficient of the feed hole (211), and D is the diameter of the target particle; Multi-airbag (260) wave surface enhancement rounding, surface waveform function: ； Where h(x) is the normal height of the spiral plate (240) at the axial position x of the spiral channel, h is the reference radial height of the surface, A is the amplitude of the radial height change caused by the expansion of the airbag (260), sin is the sine trigonometric function, x is the axial distance along the spiral channel, and λ is the wavelength of the waveform, i.e. the length of a complete cycle. Particle collision frequency estimation: ； Where f is the collision frequency between the particle and the waveform surface. Let λ be the average linear velocity of the particle moving along the channel, and λ be the wavelength of the waveform. Changes in particle kinetic energy: ； Where ΔE is the kinetic energy lost in each collision, and m is the particle mass. denoted as σ, where σ is the normal velocity of the particle relative to the surface instant before the collision, and e is the coefficient of restitution (0 ≤ e ≤ 1). σ is the ratio of the relative velocity after the collision to that before the collision.

9. A granulation process for a plastic screw granulator, characterized in that, The plastic screw granulator as described in claim 6 includes the following steps: S1: The melted plastic is stored in the feeding part (130) and is evenly fed into the screw extruder (120). The plastic entering the screw extruder (120) is kept warm by the heat insulation part (140) and is pre-cooled by the cooling part (150) when it reaches the outlet. The temperature of the unextruded plastic is reduced in advance so that it can quickly reach the conditions for subsequent cutting into granules. S2: The plastic extruded from the output end of the screw extruder (120) is cut into granules by the rotating blade (183) driven by the motor (181). The cut plastic granules are collected by the hopper (184), fall into the inner cylinder (230), and land on the rotating plate (250). S3: The outer cylinder (210) and inner cylinder (230) are driven to rotate by motor two (220). During the rotation, due to the centrifugal force, the plastic particles enter the spiral plate (240) and spiral upward. S4: As the plastic granules spiral upward, they gradually become round. During the rotation and rolling process, they gradually cool down and are formed. If rounded plastic granules appear during the rolling process, they can be thrown out through the feeding hole (211); they can also be thrown out from the top of the spiral plate (240). The thrown-out granules hit the rubber plate on the inner wall of the shield (160) and fall and are collected from the lower opening of the shield (160).

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