A three-rotor continuous internal mixing extrusion equipment

Abstract

This invention relates to the field of continuous internal mixing and extrusion equipment technology, and discloses a three-rotor continuous internal mixing and extrusion equipment, including a mixer housing, rotors one, two, and three arranged side by side in the mixer housing, a feed port on the mixer housing, and a drive mechanism. Through axial partitioning of "conveyance, pre-dispersion, high-pressure crushing, and homogenization," the conveying function and the ultra-fine dispersion function are decoupled in physical space. The second mixing zone can focus on establishing an extreme shear environment sufficient to break up stubborn carbon black agglomerates, while the first mixing zone and the mixing output zone ensure a high-throughput, stable supply and output of materials. This solves the inherent contradiction in traditional twin-rotor / twin-screw masterbatch production where "increasing blackness requires sacrificing output," enabling continuous and stable production of uniformly dispersed, high-blackness, and crystal-point-free masterbatch with high capacity. The optimized rotor configuration reduces unnecessary shear heat generation and pressure backflow losses, allowing energy to be more concentrated on the effective pigment dispersion process.

Description

Technical Field

[0001] This invention relates to the field of continuous internal mixing and extrusion equipment technology, specifically a three-rotor continuous internal mixing and extrusion equipment. Background Technology

[0002] As the core equipment for polymer material modification and molding, the performance of continuous internal mixing extrusion equipment directly affects the quality, production efficiency and cost of the final product. In the field of polymer material processing, the preparation of color masterbatch is a typical and demanding process. Color masterbatch is a homogeneous mixture of highly concentrated pigment and carrier resin. Its quality depends on whether the pigment particles can be fully and uniformly dispersed in the carrier resin to eliminate color difference, ensure coloring power and maintain the mechanical properties of the polymer. Currently, the industrial production of color masterbatch mainly relies on twin-screw extruders or twin-rotor continuous internal mixers. The basic process usually includes: premixing the carrier resin with a high proportion of pigments and other additives, and then feeding it into the extrusion or internal mixer; under the conveying, shearing and mixing action of the twin screw or twin rotor, the pigment agglomerates are broken down and gradually dispersed in the molten resin matrix, and finally the color masterbatch product is obtained by extrusion through the die, cooling and pelletizing. In particular, under the background of circular economy and sustainable development, using waste plastics as raw materials for the production of color masterbatches, especially recycled black masterbatches, has become an important development direction for the industry. The typical process is as follows: waste plastics are recycled, cleaned, mixed, crushed, and granulated to obtain recycled plastic granules, which are then blended with high-concentration pigments and then processed through intensive extrusion and molding steps to produce recycled color masterbatches. This process not only realizes the resource utilization of waste plastics, but also reduces the dependence on virgin resins. However, applying waste plastics to masterbatch production presents a more severe challenge to existing twin-screw or twin-rotor continuous mixing technologies: High complexity of raw materials: The recycled waste plastics have complex compositions and may contain impurities and degradation products. Furthermore, their melt rheological properties are unstable, which places extremely high demands on the stability and mixing uniformity of the internal mixing and extrusion process. Difficulty in dispersion: In order to cover the impurities of waste plastic and achieve the ideal coloring effect, a higher proportion of pigment is often required; pigments with high filling amounts are difficult to achieve ideal nano / micron level dispersion in recycled plastic melts with potentially uneven viscosity, which can easily lead to uneven coloring power of masterbatch, black spots or color differences. The contradiction between "dispersion" and "capacity": Existing twin-screw equipment or twin-rotor continuous internal mixers often use dense kneading blocks or anti-thread elements to enhance the dispersion effect; however, this design will significantly increase melt resistance and reduce axial conveying capacity, resulting in limited capacity and increased unit energy consumption; for the production of recycled masterbatch that needs to process large amounts of low-cost waste plastics, the balance between high capacity and high quality is a key industry pain point. Equipment wear and insufficient process flexibility: High-filling pigments and possible impurities will accelerate the wear of rotors and barrels; at the same time, existing equipment is difficult to flexibly and online adjust the shear strength to adapt to changes in the formulation of different batches of waste plastics or pigments without replacing rotor components, which affects the continuity and economy of production.

[0003] In summary, existing twin-screw extruders or twin-rotor continuous internal mixers exhibit inherent limitations when handling specific applications such as recycled plastic masterbatches, which have extremely high requirements for dispersion quality, capacity, raw material adaptability, and equipment durability. Therefore, there is an urgent need in this field for an innovative continuous internal mixing extrusion equipment solution that can maintain high conveying efficiency while ensuring or even improving ultrafine dispersion quality, and possess greater process adaptability and operational flexibility to meet the processing needs of high-end recycled masterbatches and other high-performance composite materials in the context of a circular economy. Summary of the Invention

[0004] The purpose of this application is to provide a three-rotor continuous internal mixing extrusion apparatus.

[0005] In one aspect, the three-rotor continuous internal mixing extrusion equipment provided in this application adopts the following technical solution: it includes a mixing mill housing, rotor one, rotor two, and rotor three arranged side by side in the mixing mill housing, a feeding port on the mixing mill housing, a drive mechanism, and an extruder at the discharge end. The structures of rotor one, rotor two, and rotor three are consistent. Rotor one is provided with a conveying zone, a first mixing zone, a first transition zone, a second mixing zone, a second transition zone, and a mixing output zone in sequence along its axial direction from the feeding end to the discharge end. The first mixing zone has a forward rotor ridge, the length of which is greater than the length of the reverse rotor ridge, and is configured to convey materials forward. The first mixing zone is mainly composed of raw materials. The second mixing zone has a reverse rotor edge, the length of which is greater than the length of the forward rotor edge. It is configured to establish a high-pressure zone for high-shear mixing and dispersion of the material. The rotor edge of the mixing output zone has a forward rotor edge, configured to compensate for the dispersion of the material and push it forward. The forward conveying capacity of the first mixing zone, the dispersion pressure establishment capacity of the second mixing zone, and the compensation conveying capacity of the mixing output zone are matched to achieve continuous and stable material processing. The feeding port is located at the top of the conveying zone. The discharge end of the mixing machine housing is equipped with an extruder, which is connected to the discharge end of the mixing output zone.

[0006] By adopting the above technical solution, the rotor is divided into six clearly defined axial zones: conveying, two mixing zones, a transition zone, and an output zone. By employing specific configurations dominated by forward or reverse rotor edges in the first and second mixing zones respectively, a progressive processing environment of "rapid conveying, high-pressure dispersion, and stable output" is physically constructed on a single rotor. This design fundamentally solves the contradiction between dispersion capacity and conveying efficiency inherent in traditional rotors. Simultaneously, the three rotors are structurally compatible, and the capabilities of each zone are matched, ensuring the continuous and controllable flow path, pressure field, and shear field of the material within the meshing space of the three rotors. This achieves high dispersion quality (especially suitable for pigments and nanofillers) while maintaining high production capacity and a stable mixing and extrusion process. The extruder at the end of the mixing output zone conveys the fully dispersed melt under stable pressure for extrusion molding, or it can be conveyed to the subsequent granulation unit, ensuring the uniformity and consistency of the granulated product.

[0007] Preferably, the thickness of the rotor ribs in the first mixing zone, the second mixing zone, and the mixing output zone is 11 mm, the thickness of the rotor ribs in the first transition zone and the second transition zone is 9 mm, the helix angle of the rotor ribs in the first mixing zone is 31°55′36″, the helix angle of the rotor ribs at the upstream end of the second mixing zone is 36°57′29″, the helix angle of the rotor ribs at the downstream end is 28°57′29″, and the helix angle of the rotor ribs in the mixing output zone is 27°41′11″.

[0008] By adopting the above technical solution, optimized structural parameters are provided. The thicker rotor ribs of 11 mm ensure the structural strength and wear resistance of the main body of the mixing and output sections. The 9 mm thick ribs of the transition zone achieve a flexible transition of functions. The precise helix angle value (especially the decreasing angle of the second mixing zone) is the best balance point verified by simulation and experiment. It can maximize the pressure accumulation and dispersion intensity of the second mixing zone while ensuring sufficient conveying power, and at the same time ensure the smooth homogenization of the output section. These specific parameters make the rotor design have excellent reproducibility and process reliability, and are especially suitable for high-end material processing with stringent requirements for dispersion uniformity.

[0009] Preferably, rotor one, rotor two, and rotor three are made of a heat-treated material with a hardened layer on their surface.

[0010] By adopting the above technical solutions, the rotor is endowed with excellent comprehensive mechanical properties. The quenching and tempering treatment (quenching and high-temperature tempering) gives the rotor matrix a combination of high strength and good toughness (such as hardness H250-280), which can withstand the huge torque and alternating stress generated by the high-pressure mixing zone. The surface hardening layer (such as a hardened layer with a depth of 0.45-0.75mm and a hardness of HV900-980 obtained by oxidation treatment) greatly improves the wear resistance and corrosion resistance of the rotor surface, effectively resisting the wear of materials, especially melts filled with hard pigments or fillers, on the rotor edges, thereby significantly extending the service life of the rotor and ensuring the stability of machining accuracy during long-term operation.

[0011] Preferably, the drive mechanism is used to drive rotor one, rotor two, and rotor three. The drive mechanism is fixed to the right end of the internal mixer housing. The drive mechanism includes a protective frame, a gap adjustment drive mechanism, and a synchronous movement mechanism. The protective frame is fixed to the right end of the internal mixer housing. The gap adjustment drive mechanism is installed inside the protective frame. The synchronous movement mechanism is provided at the bottom of the gap adjustment drive mechanism.

[0012] By adopting the above technical solution, an integrated dedicated drive solution is provided, which integrates the drive, gap adjustment and synchronous linkage mechanism into the protective frame. The structure is compact and easy to install and maintain. The independent gap adjustment drive mechanism allows for independent or associated control of the drive state of the three rotors, while the synchronous linkage mechanism ensures that the displacement of the associated rotors can be accurately synchronized during the adjustment process. This is the key to achieving precise meshing and gap adjustment of the three rotors, and provides a hardware foundation for the equipment to adapt to materials of different viscosities or wear compensation.

[0013] Preferably, the gap adjustment drive mechanism includes a geared motor, a rotating shaft, a receiving seat, bevel gear one, bevel gear two, a bearing seat, a movable seat one, bevel gear three, bevel gear four, movable seat two, bevel gear five, and bevel gear six. The front end of the geared motor is bolted to the protective frame. The geared motor is connected to the rotating shaft via a coupling. The rotating shaft is movably connected to the inner side of the receiving seat, and the right end of the receiving seat is fixed to the protective frame. Bevel gear five, bevel gear one, and bevel gear three are distributed sequentially from front to back along the axial direction of the rotating shaft, and the rotating shaft is respectively connected to bevel gear five, bevel gear one, and bevel gear three. The rear end of bevel gear one is movably connected to the receiving seat. The rear ends of bevel gear one and bevel gear two mesh and drive each other. The left end of bevel gear two is movably connected to the inner side of the receiving seat and is also driven by rotor two. The front end of bevel gear three is movably connected to moving seat one. The front end of bevel gear three meshes and drives each other. The left end of bevel gear four is movably connected to moving seat one and is also driven by rotor one. The front end of bevel gear five is movably connected to moving seat two. The front end of bevel gear five meshes and drives each other. The left end of bevel gear six is ​​movably connected to moving seat two and is driven by rotor three. The co-movement mechanism is located at the bottom of moving seat one and moving seat two.

[0014] By adopting the above technical solution, a clever coaxial bevel gear transmission system was designed. On a single shaft driven by a geared motor, three fixed or sliding bevel gears transmit power to three sets of driven bevel gears, thereby driving three rotors. This layout provides a clear power transmission path and a symmetrical structure, which helps ensure the synchronization of the rotational speeds of multiple rotors. Specifically, the bevel gear sets (three / four, five / six) connected to rotor one and rotor three are mounted on movable seats. This allows for the adjustment of the radial position of rotor one and rotor three relative to the central rotor two, while the drive assembly of the central rotor two remains fixed, serving as the adjustment reference.

[0015] Preferably, the tooth angles of bevel gear five and bevel gear three are set in the same direction, and the tooth angle of bevel gear one is set in the opposite direction to that of bevel gear five and bevel gear three.

[0016] By adopting the above technical solution and precisely designing the meshing direction of the bevel gears, the rotation direction of the three rotors is determined. Bevel gear five and bevel gear three are in the same direction, so that the rotor three they drive has the same direction of rotation as rotor one. However, the tooth angle of bevel gear one is opposite, so that the central rotor two it drives has the opposite direction of rotation to the former two. This combination of "two positive and one negative" or "one positive and two negative" rotation is the key to achieving efficient mixing and self-cleaning functions in the three-rotor continuous internal mixer. It can generate strong shearing and material exchange between the rotors, which complements the partitioned rotor design of this invention and jointly optimizes the dispersion effect.

[0017] Preferably, the rotating shaft has sliding grooves on both the front and rear sides, the bevel gear three slides with the sliding groove at the rear end, and the bevel gear five slides with the sliding groove at the front end.

[0018] By adopting the above technical solution, the sliding engagement between the slide groove and bevel gears three and five is the key innovation. It allows the driving bevel gear to slide along the axis of the shaft (i.e., the front-to-back direction) while the shaft rotates. This design decouples the power transmission and position adjustment functions: no matter how the moving seats one and two drive the rotor and the driven bevel gear to move radially to adjust the clearance, bevel gears three and five can adapt to the new meshing position by sliding along the slide groove, always maintaining the power connection with the shaft and the correct meshing with the driven bevel gear. This ensures that the drive system can still work stably and efficiently without power loss during and after the clearance adjustment process.

[0019] Preferably, the synchronous mechanism includes a support plate, a first guide rail, a first slide plate, a first push rod, a hydraulic cylinder, a friction turntable, a second push rod, a second slide plate, a second guide rail, and a guide wheel seat. The bottom of the support plate is fixed to the protective frame. The first and second guide rails are arranged opposite each other on the front and rear sides of the top of the support plate. The first slide plate is slidably engaged with the top of the first guide rail. The first slide plate is bolted to the bottom of the first push rod. The top of the first slide plate is fixed to the movable seat. The first push rod is tightly fitted to the left end wall of the friction turntable. The top of the hydraulic cylinder is fixed to the support plate. The rear end of the friction turntable is movably connected to the support plate. The output end of the hydraulic cylinder is fixed to the bottom right end of the first slide plate. The second push rod is tightly fitted to the right end wall of the friction turntable. The second push rod is bolted to the top of the second slide plate. The second slide plate is slidably engaged with the top of the second guide rail.

[0020] By adopting the above technical solution, a mechanically forced synchronization precision adjustment mechanism is provided. The hydraulic cylinder serves as a single power source, directly driving the slide plate 1 and the connected movable seat 1 (control rotor 1) to move along the guide rail. Simultaneously, the slide plate 1 pushes the friction disc that can rotate around the axis through the push rod 1. Since the push rods 1 and 2 are respectively closely attached to the symmetrical positions on both sides of the friction disc, the rotation of the friction disc will push the push rod 2 with the same force arm and direction, thereby driving the slide plate 2 and the movable seat 2 (control rotor 3) to perform completely symmetrical reverse movements. This mechanism ensures that rotor 1 and rotor 3 always move synchronously in opposite directions relative to the fixed center rotor 2 during adjustment. This is the fundamental guarantee for maintaining the parallelism of the three rotor axes and the uniformity of the meshing gap, avoiding the errors and asynchrony problems that may be caused by manual adjustment.

[0021] Preferably, guide wheel seats are provided on the left and right sides of the top of the support plate, with the guide wheel seat on the left end being in close contact with the left end wall of push rod one, and the guide wheel seat on the right end being in close contact with the right end wall of push rod two.

[0022] By adopting the above technical solution, the guide wheel seats play a key guiding and limiting role. They constrain push rod one and push rod two from the outside, respectively, to ensure that the push rods can only move horizontally under the push of the hydraulic cylinder or the drive of the friction turntable, without deflection or lateral displacement. This further improves the motion accuracy and rigidity of the entire synchronous mechanism, making the contact pressure between the push rod and the friction turntable stable, and the force transmission more direct and lossless, thereby ensuring the smoothness of the gap adjustment process, the repeatability of positioning accuracy, and the reliability of long-term use.

[0023] In summary, this application includes at least one of the following beneficial technical effects of a three-rotor continuous internal mixing extrusion apparatus: 1. By dividing the process into axial zones for "conveyance, pre-dispersion, high-pressure crushing, and homogenization," the conveying and ultra-fine dispersion functions are physically decoupled. The second mixing zone can focus on creating an extreme shear environment sufficient to break up stubborn carbon black agglomerates, while the first mixing zone and the mixing output zone ensure a high-throughput and stable supply and output of materials. This completely solves the inherent contradiction in traditional twin-rotor / twin-screw masterbatch production that "to increase blackness, output must be sacrificed," enabling the continuous and stable production of high-quality granular products with uniform dispersion, high blackness, and no crystal points at high capacity. 2. The optimized rotor configuration reduces unnecessary shear heat generation and pressure backflow losses, allowing energy to be more concentrated in the effective pigment dispersion process. When dealing with high-viscosity waste plastics, adjusting the gap can significantly reduce energy consumption per unit output. The online gap adjustment function of the equipment provides unparalleled process flexibility. Operators can fine-tune the meshing gap based on real-time melt pressure or torque feedback, keeping the production process in an optimal state at all times. This effectively buffers the impact of raw material fluctuations on product quality and greatly improves the consistency and pass rate of recycled masterbatch products. 3. Due to the ability to achieve better pigment dispersion, the recycled black masterbatch produced using this equipment can achieve or even exceed the level of ordinary masterbatch produced using virgin resin in terms of tinting strength, hiding power and uniformity; this gives recycled masterbatch made from waste plastics the technical capital to enter the mid-to-high-end application market and greatly enhances the economic value of recycled plastics. 4. By "solidifying" the complex masterbatch dispersion process into the physical structure of the rotor and fine-tuning it through a quantifiable and adjustable drive mechanism, the production process is transformed from a "skill" that relies on operator experience into a controllable and repeatable "precision engineering". This is conducive to achieving standardization, automation and intelligence in production, which is in line with the development direction of modern intelligent manufacturing.

[0024] 5. This equipment efficiently connects the extruder at the end of the mixing output zone with the granulation unit, ensuring stable melt pressure output and extrusion molding. It can also be directly adapted to underwater granulation, air-cooled granulation, or water ring granulation units, significantly improving the uniformity and yield of granulated products, meeting the high standards of the molding equipment field. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the rotor planar structure in Embodiment 1 of the present invention; Figure 3 This is a partial enlarged structural diagram of the rotor in Embodiment 1 of the present invention; Figure 4 This is a schematic cross-sectional view of the drive mechanism in Embodiment 1 of the present invention; Figure 5 This is a schematic cross-sectional view of the gap adjustment drive mechanism in Embodiment 2 of the present invention; Figure 6 This is a schematic cross-sectional view of the synchronous mechanism in Embodiment 2 of the present invention; Figure 7 This is a partially enlarged structural diagram of the synchronous mechanism in Embodiment 2 of the present invention; Figure 8 This is a three-dimensional structural diagram of the co-movement mechanism in Embodiment 2 of the present invention.

[0026] In the diagram: Internal mixer housing-1, rotor one-2, rotor two-3, rotor three-4, feed port-5, drive mechanism-6, extruder-7; Transport Zone-21, First Refining Zone-22, Transition Zone 1-23, Second Refining Zone-24, Transition Zone 2-25, Refining Output Zone-26; Protective frame-61, gap adjustment drive mechanism-62, synchronous movement mechanism-63; Gear motor-621, rotating shaft-622, bearing seat-623, bevel gear one-624, bevel gear two-625, bearing seat-626, moving seat one-627, bevel gear three-628, bevel gear four-629, moving seat two-6210, bevel gear five-6211, bevel gear six-6212, slide groove-6221; Support plate-631, guide rail one-632, slide plate one-633, push rod one-634, hydraulic cylinder-635, friction turntable-636, push rod two-637, slide plate two-638, guide rail two-639, guide wheel seat-6310. Detailed Implementation

[0027] The following is in conjunction with the appendix Figure 1 - Appendix Figure 8This application will be described in further detail below.

[0028] Example 1: A three-rotor continuous internal mixing extrusion apparatus, referring to Figures 1-4 The internal mixer includes a housing 1, rotors 2, 3, and 4 arranged side-by-side in the housing 1, a feed inlet 5 on the housing 1, and a drive mechanism 6. The structures of rotors 2, 3, and 4 are identical. Rotor 2, along its axial direction from the feed end to the discharge end, is provided with a conveying zone 21, a first mixing zone 22, a first transition zone 23, a second mixing zone 24, a second transition zone 25, and a mixing output zone 26. The first mixing zone 22 has a forward rotor ridge, the length of which is greater than the length of the reverse rotor ridge, and is configured primarily for forward material conveying. The second mixing zone 24 has a reverse rotor ridge. The reverse rotor edge of the sub-edge section has a longer reverse rotor edge than the forward rotor edge, and is configured to establish a high-pressure zone for high-shear mixing and dispersion of the material. The rotor edge of the mixing output zone 26 has a forward rotor edge, and is configured to compensate for the dispersion of the material and push it forward. The forward conveying capacity of the first mixing zone 22, the dispersion pressure establishment capacity of the second mixing zone 24, and the compensation conveying capacity of the mixing output zone 26 are matched to achieve continuous and stable material processing. The feed port 5 is located at the top of the conveying zone 21. The discharge end of the mixing machine housing 1 is equipped with an extruder 7, which is connected to the discharge end of the mixing output zone 26.

[0029] In some embodiments, the rotor edges of the first mixing zone 22, the second mixing zone 24, and the mixing output zone 26 have the same thickness. The rotor edge helix angle of the first mixing zone 22 is symmetrically arranged within its axial range. The rotor edge helix angle of the second mixing zone 24 decreases from upstream to downstream. The rotor edge helix angle of the mixing output zone 26 is symmetrically arranged within its axial range. The rotor edges of the first transition zone 23 and the second transition zone 25 have the same thickness. The drive mechanism 6 is used to drive the first rotor 2, the second rotor 3, and the third rotor 4. The drive mechanism 6 is fixed to the right end of the mixing mill housing 1. The drive mechanism 6 includes a protective frame 61, a gap adjustment drive mechanism 62, and a synchronous movement mechanism 63. The protective frame 61 is fixed to the right end of the mixing mill housing 1. The gap adjustment drive mechanism 62 is installed inside the protective frame 61. The synchronous movement mechanism 63 is provided at the bottom of the gap adjustment drive mechanism 62.

[0030] It should be noted that the conveying zone 21 is located at the rotor feeding end and usually adopts a large-lead positive rotor. Its main function is to quickly and stably receive the material from the feeding port 5 and convey it to the downstream mixing zone, while completing the initial compaction and preheating. The first mixing zone 22 serves as the primary dispersion and conveying section, with its forward rotor ridges dominating. This configuration allows it to provide a certain degree of shear mixing while maintaining strong axial pumping capacity, pressurizing the material and smoothly delivering it into the core high-shear zone. The rotor ridge helix angle is axially symmetrical and constant, ensuring the uniformity of conveying. The 11 mm rotor ridge thickness provides the necessary structural strength and wear resistance. In the transition zone 23, the rotor rib thickness is reduced to 9 mm, and the rotor rib configuration changes smoothly. Its function is to achieve a smooth transition of the flow channel from the first mixing zone 22 to the second mixing zone 24. It helps to relieve the pressure at the end of the first mixing zone and guides the material into the high-pressure zone in a more dispersed flow state, avoiding dead flow angles and sudden changes in shear stress. The second mixing zone 24, as the core high-pressure dispersion section, is dominated by the reverse rotor edge. The reverse rotor edge generates a strong resistance effect, forming a closed high-pressure chamber together with the adjacent rotor and barrel. The material here is subjected to extremely high shear rates and compression, achieving strong crushing and uniform dispersion of dispersed phases such as pigments and nanofillers. The rotor edge helix angle decreases from a larger angle upstream (36°57′29″) to a smaller angle downstream (28°57′29″). This design allows the upstream to quickly entrain the material and establish initial high pressure, while the downstream further enhances the compression and shear strength through a smaller helix angle. The 11 mm edge thickness ensures its rigidity under high pressure. Transition zone 25 is similar to transition zone 1 23, with a thickness of 9 mm. Its function is to smoothly discharge the material that has undergone severe shearing from the high-pressure second mixing zone 24, so that the pressure is initially released and the material temperature distribution is more uniform, in preparation for the final stable output. The mixing output zone 26 serves as the final homogenization and stabilization conveying section, restoring the forward rotor edge as the main component. Its small constant helix angle (27°41′11″) provides stable conveying capacity, performs final homogenization of the material, eliminates possible temperature and composition fluctuations, and pushes the material to the extruder 7 with stable pressure and flow rate. The extruder 7 outputs the fully dispersed melt at stable pressure, which facilitates efficient connection with subsequent granulation units (such as underwater granulation, air-cooled granulation, etc.) to finally form a uniform granular product.

[0031] This seven-stage design (including the extruder) of "conveying-primary mixing / conveying-transition-high-pressure dispersion-transition-homogenization output-extrusion" physically plans the processing journey of the material on a single rotor and subsequent extrusion unit, realizing the orderly separation and efficient synergy of functions in space. Rotor materials and treatment: Rotors 1-2, 2-3, and 3-4 are made of alloy steel through quenching and tempering treatment, giving the core excellent comprehensive mechanical properties with a hardness of approximately H250-280, combining strength and toughness; the surface is hardened through nitriding or oxidation to form a hardened layer with a depth of 0.45~0.75mm and a hardness of HV900~980, which greatly improves wear resistance and corrosion resistance, making it especially suitable for long-term operation of highly filled materials; Equipment layout and drive: Three rotors are arranged in a straight line inside the internal mixer housing 1; the feed port 5 is precisely located above the conveying zone 21 to ensure that the material can directly enter the conveying section; the drive mechanism 6 is integrated at the right end of the housing, and its protective frame 61 provides protection for the internal transmission components; the drive mechanism integrates the gap adjustment drive mechanism 62 and the synchronous drive mechanism 63, indicating that this equipment not only has a drive function, but also integrates the ability to adjust the rotor meshing gap online, which is another important innovation of this invention.

[0032] Example 2: A three-rotor continuous internal mixing extrusion granulation equipment, referring to... Figures 5-8The clearance adjustment drive mechanism 62 includes a geared motor 621, a rotating shaft 622, a bearing seat 623, a first bevel gear 624, a second bevel gear 625, a bearing seat 626, a first movable seat 627, a third bevel gear 628, a fourth bevel gear 629, a second movable seat 6210, a fifth bevel gear 6211, and a sixth bevel gear 6212. The front end of the geared motor 621 is bolted to the protective frame 61. The geared motor 621 is connected to the rotating shaft 622 via a coupling. The rotating shaft 622 is movably connected to the inner side of the bearing seat 623, and the bearing... The right end of the receiving seat 623 is fixed to the protective frame 61. Along its axial direction, the rotating shaft 622 has bevel gears 6211 (five), 624 (one), and 628 (three) distributed sequentially from front to back. The rotating shaft 622 is connected to bevel gears 6211, 624, and 628 respectively. The rear end of bevel gear 624 is movably connected to the receiving seat 623. Bevel gear 624 meshes with the rear end of bevel gear 625. The left end of bevel gear 625 is movably connected to the inner side of the receiving seat 623. 25 is connected to rotor 2 3 for transmission; the front end of bevel gear 3 628 is movably connected to movable seat 1 627; bevel gear 3 628 meshes with the front end of bevel gear 4 629 for transmission; the left end of bevel gear 4 629 is movably connected to movable seat 1 627 and is also connected to rotor 1 2 for transmission; the front end of bevel gear 5 6211 is movably connected to movable seat 2 6210; bevel gear 5 6211 meshes with the front end of bevel gear 6212 for transmission; the left end of bevel gear 6212 is movably connected to movable seat 2 6210; bevel... Gear 6212 is connected to rotor 34 via a transmission. The synchronous mechanism 63 is located at the bottom of movable seat 1 627 and movable seat 2 6210. The tooth angles of bevel gear 5 6211 and bevel gear 3 628 are set in the same direction. The tooth angle of bevel gear 1 624 is set opposite to that of bevel gear 5 6211 and bevel gear 3 628. Sliding grooves 6221 are provided on both the front and rear sides of the rotating shaft 622. Bevel gear 3 628 is slidably engaged with the sliding groove 6221 located at the rear end, and bevel gear 5 6211 is slidably engaged with the sliding groove 6221 located at the front end.

[0033] In this application, the synchronous mechanism 63 includes a support plate 631, a first guide rail 632, a first slide plate 633, a first push rod 634, a hydraulic cylinder 635, a friction turntable 636, a second push rod 637, a second slide plate 638, a second guide rail 639, and a guide wheel seat 6310. The bottom of the support plate 631 is fixed to the protective frame 61. The first guide rail 632 and the second guide rail 639 are arranged opposite each other on the front and rear sides of the top of the support plate 631. The first slide plate 633 slides in cooperation with the top of the first guide rail 632. The bottom of the first slide plate 633 is bolted to the first push rod 634. The top of the first slide plate 633 is fixed to the first movable seat 627. The first push rod 634 is tightly connected to the left end wall of the friction turntable 636. The hydraulic cylinder 635 is fixed to the top of the support plate 631, the rear end of the friction turntable 636 is movably connected to the support plate 631, the output end of the hydraulic cylinder 635 is fixed to the bottom right end of the slide plate 633, the push rod 637 is tightly fitted to the right end wall of the friction turntable 636, the push rod 637 is bolted to the top of the slide plate 638, the slide plate 638 is slidably fitted to the top of the guide rail 639, and the top left and right sides of the support plate 631 are provided with guide wheel seats 6310. The guide wheel seat 6310 located on the left end is tightly fitted to the left end wall of the push rod 634, and the guide wheel seat 6310 located on the right end is tightly fitted to the right end wall of the push rod 637.

[0034] It should be noted that the geared motor 621 provides power and drives a through shaft 622 through a coupling. The shaft 622 is supported on the bearing seat 623 by bearings. Rotor 2 3 drive: Bevel gear 1 624 fixed in the middle of the rotating shaft 622 meshes with bevel gear 2 625 fixed on the bearing seat 623. Bevel gear 2 625 directly drives rotor 2 3. Since the bearing seat 623 is fixed, the axial and radial positions of rotor 2 3 are fixed during operation, serving as the reference for the entire system. Rotor 1 2 and Rotor 3 4 Drive and Adjustability: Bevel gear 3 628 and bevel gear 5 6211 are connected to the rotating shaft 622 via splines or sliding keys, and can slide axially along the rear end slide groove 6221 and the front end slide groove 6221 opened on the rotating shaft 622, respectively. They mesh with bevel gear 4 629 and bevel gear 6212 installed on the moving seat 1 627 and the moving seat 2 6210, respectively, thereby driving rotor 1 2 and rotor 3 4; Rotation direction control: The tooth angles of bevel gear 3 628 and bevel gear 5 6211 are set in the same direction, while the tooth angle of bevel gear 1 624 is opposite to that of bevel gear 3. This design allows rotor 1 2 and rotor 3 4 to obtain the same rotation direction, while rotor 2 3 obtains the opposite rotation direction, forming an optimized "same direction / opposite direction" combined rotation mode to generate efficient shearing and material exchange. Adjustment principle: When it is necessary to adjust the meshing clearance between rotor one and rotor three and center rotor two, the moving seat one 627 and the moving seat two 6210 will drive rotor one and three, as well as bevel gears four and six, to move radially together; at this time, bevel gears three and five, which are meshed with them, adapt to the slight change in the gear center distance caused by the radial movement by sliding in the rotating shaft slide groove 6221, so as to maintain the correct meshing state without stopping the machine or interrupting the power transmission. Synchronous mechanism 63 (precision synchronous adjustment actuator): Execution and guidance: The hydraulic cylinder 635 serves as the power source, with its cylinder body fixed on the support plate 631 and the piston rod end connected to the slide plate 633; ​​the slide plate 633 is constrained by the guide rail 632 and can only move horizontally; the upper part of the slide plate 633 is fixed with the moving seat 627. Synchronization principle: When hydraulic cylinder 635 extends, it pushes slide plate 633 and rotor 1 to move to the left; push rod 634 moves to the left and pushes friction disc 636 to rotate clockwise; due to the rotation of friction disc 636, its right side pushes push rod 637 to the right with the same lever arm, thereby driving slide plate 638 and rotor 3 to move to the right; this process forces rotor 1 and rotor 3 to move precisely synchronously with respect to the central rotor 2 at equal distances and in opposite directions. Enhanced stability: The guide wheel seats 6310, located on the left and right sides of the support plate 631, are closely attached to push rod 1 634 and push rod 2 637 from the outside, respectively, which restricts the lateral swing of the push rod and ensures that the push rod can only move along a strict straight line, thereby improving the rigidity, motion accuracy and repeatability of the entire adjustment system.

[0035] This invention provides a three-rotor continuous internal mixing extrusion granulation equipment that is particularly suitable for the production of color masterbatch, especially for the production of recycled color masterbatch made from waste plastics. Taking the production of recycled black masterbatch as an example (the raw materials are waste plastic granules and high-concentration carbon black), the material processing in the rotor follows a preset "programmed" path: Conveying Zone 21: The premixed waste plastic granules and carbon black mixture is forcibly sucked in from the feed port 5 located directly above the conveying zone 21; the large-lead rotor in this zone rapidly conveys and compacts the loose material forward. Under the action of mechanical friction and external heating, the waste plastic begins to melt and undergoes preliminary macroscopic impregnation and mixing with the carbon black; the high conveying efficiency of this section ensures that a large amount of material can be processed quickly, laying the foundation for high production capacity; First mixing zone 22: The material enters the first mixing zone 22, which is mainly driven by forward conveying; here, the material is further compressed, the pressure continues to rise, and the waste plastic is completely melted; the dominant role of the forward rotor edge ensures the continuity of the material flow and prevents the flow obstruction that may be caused by high carbon black filling; at the same time, the initial shearing action begins to break up the larger carbon black agglomerates, achieving "pre-dispersion", preparing for the subsequent nanoscale dispersion, and stabilizing the temperature and viscosity of the material; Transition Zone 1 23: This thin-edged transition zone is a key design feature; it smoothly guides the material from a flow field dominated by conveying to a high-shear flow field. For recycled plastic melts with complex composition and varying rheological properties, this transition effectively avoids local pigment aggregation or shear overheating caused by abrupt changes in the flow field, ensuring that carbon black particles can enter the core dispersion zone with a more uniform concentration. Second mixing zone 24: This is the core area that determines the color strength and blackness of the masterbatch; this section, dominated by the reverse rotor ridges, strongly impedes the flow of materials, establishing a local ultra-high pressure in the closed chamber formed with the adjacent rotors that is much higher than that of traditional dual rotors; under this high-pressure environment, in conjunction with the high-frequency and high-intensity shear field generated by the meshing of the three rotors, the primary and secondary agglomerates of carbon black are effectively mechanically broken down to a finer scale; the design of the rotor ridge helix angle decreasing makes the material quickly drawn into the high-pressure zone upstream, and subjected to strong compression and shearing for a longer time downstream, ensuring that even for carbon black that is difficult to disperse or aged plastic matrix that has undergone multiple processing, ideal dispersion effect can be achieved; Transition Zone 25: After intense shearing, the melt containing ultrafine dispersed carbon black has a high temperature and concentrated pressure; Transition Zone 25 allows the pressure to be released gradually, and the heat is redistributed evenly in the material, preventing the generation of bubbles or re-agglomeration of pigments due to sudden pressure relief, thus stabilizing the dispersion state. Internal mixing output zone 26: In the final stage, the smaller forward rotor helix angle provides a stable pumping force; the main function of this zone is to eliminate dispersion dead zones and concentration gradients, ensuring that the carbon black concentration and dispersion in the melt flowing out from different positions of the rotor are completely consistent, thereby producing high-quality masterbatch with minimal color difference and stable coloring power, and pushing it to the extruder 7 at a constant pressure and flow rate. After being output through the extruder die, it is extruded and shaped, and can also enter the granulation unit (such as underwater granulation, air-cooled granulation, etc.) to finally form a uniform granular product.

[0036] The sources of waste plastics are complex, and their melt viscosity and impurity content may vary from batch to batch; the drive adjustment mechanism of this invention provides dynamic adaptability for this purpose. Gap adjustment to cope with viscosity changes: When processing a batch of waste plastic with high melt viscosity, the synchronous mechanism 63 can be activated to move the two rotors (2 and 4) synchronously and in opposite directions through the hydraulic cylinder 635, and appropriately increase the meshing gap between them and the central rotor 3; this can reduce the shearing intensity and driving torque, avoid equipment overload, and at the same time ensure basic mixing effect, realizing rapid switching between "strong shearing" and "weak shearing" modes; Wear and maintenance: Long-term processing of waste plastics containing impurities will accelerate wear; when wear is detected to cause increased gap and decreased dispersion effect, the meshing gap can be reduced synchronously by the synchronous mechanism to compensate for the wear, restore the original shear strength and dispersion ability, significantly extend the effective production cycle and reduce the maintenance frequency; Uninterrupted power ensures continuous production: All the above adjustments are completed through the cooperation of the slide 6221 and the sliding bevel gear during equipment operation and continuous power transmission, truly realizing "online self-adaptive" production based on material characteristics, which is crucial for recycling and granulation production lines that need to continuously process waste plastics on a large scale.

[0037] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A three-rotor continuous internal mixing extrusion apparatus, comprising an internal mixer housing (1), rotor one (2), rotor two (3), and rotor three (4) arranged side by side in the internal mixer housing (1), a feed port (5) provided on the internal mixer housing (1), and a drive mechanism (6), characterized in that: The structures of rotor one (2), rotor two (3), and rotor three (4) are consistent. Rotor one (2) is provided with a conveying zone (21), a first mixing zone (22), a transition zone one (23), a second mixing zone (24), a transition zone two (25), and a mixing output zone (26) in sequence from the feed end to the discharge end along its axial direction. The first mixing zone (22) has a forward rotor ridge, the length of which is greater than the length of the reverse rotor ridge, and is configured to mainly convey materials forward. The second mixing zone (24) has a reverse rotor ridge, the length of which is greater than the length of the forward rotor ridge, and is configured to establish a conveying zone. In the high-pressure zone, the material is subjected to high-shear mixing and dispersion refinement. The spiral of the mixing output zone (26) has a forward rotor edge, which is configured to compensate for the dispersion of the material and push it forward. The forward conveying capacity of the first mixing zone (22), the dispersion pressure establishment capacity of the second mixing zone (24), and the compensation conveying capacity of the mixing output zone (26) are matched to realize the continuous and stable processing of the material. The feeding port (5) is located at the top of the conveying zone (21). The discharge end of the mixing machine box (1) is equipped with an extruder (7), which is connected to the discharge end of the mixing output zone (26).

2. The three-rotor continuous internal mixing extrusion apparatus according to claim 1, characterized in that: The rotor edges of the first mixing zone (22), the second mixing zone (24), and the mixing output zone (26) have the same thickness. The rotor edge helix angle of the first mixing zone (22) is symmetrically set within its axial range. The rotor edge helix angle of the second mixing zone (24) decreases from upstream to downstream. The rotor edge helix angle of the mixing output zone (26) is symmetrically set within its axial range. The rotor edges of the first transition zone (23) and the second transition zone (25) have the same thickness.

3. The three-rotor continuous internal mixing extrusion apparatus according to claim 1, characterized in that: The thickness of the rotor ribs in the first mixing zone (22), the second mixing zone (24), and the mixing output zone (26) is 11 mm. The thickness of the rotor ribs in the first transition zone (23) and the second transition zone (25) is 9 mm. The rotor rib helix angle of the first mixing zone (22) is 31°55′36″. The rotor rib helix angle at the upstream end of the second mixing zone (24) is 36°57′29″. The rotor rib helix angle at the downstream end is 28°57′29″. The rotor rib helix angle of the mixing output zone (26) is 27°41′11″.

4. A three-rotor continuous internal mixing extrusion apparatus according to claim 1, characterized in that: The rotors 1 (2), 2 (3), and 3 (4) are made of heat-treated material with a hardened layer on their surface.

5. A three-rotor continuous internal mixing extrusion apparatus according to claim 1, characterized in that: The drive mechanism (6) is used to drive rotor one (2), rotor two (3) and rotor three (4). The drive mechanism (6) is fixed to the right end of the internal mixer housing (1). The drive mechanism (6) includes a protective frame (61), a gap adjustment drive mechanism (62) and a synchronous mechanism (63). The protective frame (61) is fixed to the right end of the internal mixer housing (1). The gap adjustment drive mechanism (62) is installed inside the protective frame (61). The synchronous mechanism (63) is provided at the bottom of the gap adjustment drive mechanism (62).

6. A three-rotor continuous internal mixing extrusion apparatus according to claim 5, characterized in that: The gap adjustment drive mechanism (62) includes a geared motor (621), a rotating shaft (622), a bearing seat (623), a first bevel gear (624), a second bevel gear (625), a bearing seat (626), a first movable seat (627), a third bevel gear (628), a fourth bevel gear (629), a second movable seat (6210), a fifth bevel gear (6211), and a sixth bevel gear (6212). The front end of the geared motor (621) is bolted to the protective frame (61), and the geared motor (621) is equipped with a coupling. The shaft (622) is connected to the rotating shaft (622) and is movably connected to the inner side of the bearing seat (623). The right end of the bearing seat (623) is fixed to the protective frame (61). The rotating shaft (622) has bevel gear five (6211), bevel gear one (624), and bevel gear three (628) distributed sequentially from front to back along its axial direction. The rotating shaft (622) is connected to bevel gear five (6211), bevel gear one (624), and bevel gear three (628) respectively. The rear end of bevel gear one (624) is connected to the bearing seat. The receiving seat (623) is movably connected, and the rear ends of the first bevel gear (624) and the second bevel gear (625) mesh and drive each other. The left end of the second bevel gear (625) is movably connected to the inner side of the receiving seat (623), and the second bevel gear (625) is drivingly connected to the second rotor (3). The front end of the third bevel gear (628) is movably connected to the first movable seat (627), and the front end of the third bevel gear (628) meshes and drives each other. The left end of the fourth bevel gear (629) is movably connected to the first movable seat (627). The bevel gear 4 (629) is connected to the rotor 1 (2) in a transmission connection. The front end of the bevel gear 5 (6211) is movably connected to the movable seat 2 (6210). The front end of the bevel gear 5 (6211) is meshed with the front end of the bevel gear 6 (6212). The left end of the bevel gear 6 (6212) is movably connected to the movable seat 2 (6210). The bevel gear 6 (6212) is connected to the rotor 3 (4) in a transmission connection. The co-movement mechanism (63) is located at the bottom of the movable seat 1 (627) and the movable seat 2 (6210).

7. A three-rotor continuous internal mixing extrusion apparatus according to claim 6, characterized in that: The tooth angles of the five bevel gears (6211) and the three bevel gears (628) are set in the same direction, while the tooth angle of the one bevel gear (624) is set in the opposite direction to that of the five bevel gears (6211) and the three bevel gears (628).

8. A three-rotor continuous internal mixing extrusion apparatus according to claim 6, characterized in that: The rotating shaft (622) has sliding grooves (6221) on both the front and rear sides. The bevel gear three (628) is slidably engaged with the sliding groove (6221) at the rear end, and the bevel gear five (6211) is slidably engaged with the sliding groove (6221) at the front end.

9. A three-rotor continuous internal mixing extrusion apparatus according to claim 6, characterized in that: The co-movement mechanism (63) includes a support plate (631), a guide rail one (632), a slide plate one (633), a push rod one (634), a hydraulic cylinder (635), a friction turntable (636), a push rod two (637), a slide plate two (638), a guide rail two (639), and a guide wheel seat (6310). The bottom of the support plate (631) is fixed to the protective frame (61). The top front and rear sides of the support plate (631) are provided with guide rail one (632) and guide rail two (639). The slide plate one (633) slides with the top of the guide rail one (632). The slide plate one (633) is bolted to the bottom of the push rod one (634). The top of the first sliding plate (633) is fixed to the first movable seat (627), the first push rod (634) is tightly fitted to the left end wall of the friction turntable (636), the top of the hydraulic cylinder (635) is fixed to the support plate (631), the rear end of the friction turntable (636) is movably connected to the support plate (631), the output end of the hydraulic cylinder (635) is fixed to the bottom right end of the first sliding plate (633), the second push rod (637) is tightly fitted to the right end wall of the friction turntable (636), the second push rod (637) is bolted to the top of the second sliding plate (638), and the second sliding plate (638) is slidably fitted to the top of the second guide rail (639).

10. A three-rotor continuous internal mixing extrusion apparatus according to claim 9, characterized in that: The top left and right sides of the support plate (631) are provided with guide wheel seats (6310). The guide wheel seat (6310) at the left end is closely fitted with the left end wall of push rod one (634), and the guide wheel seat (6310) at the right end is closely fitted with the right end wall of push rod two (637).

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