A multi-screw synchronous screw multi-mixer barrel screw

Abstract

The present application relates to the field of mixing and extruding equipment, and discloses a multi-screw synchronous spiral multi-mixing barrel screw, which comprises a feeding port, a natural exhaust port, a vacuum exhaust port, a discharging port, a gear box reducer, and a barrel component, the barrel component is provided with a single hole at the feeding end and four holes at the discharging end, and a transmission unit with a plurality of small circumferential screws is arranged in the barrel component, and the feeding port, the natural exhaust port, the vacuum exhaust port and the discharging port are distributed along the axial direction of the barrel component.In the present application, the composite structure of the single screw in the feeding section and the plurality of small circumferential screws is adopted, and various mixing units on the small screws are matched, so that multi-dimensional stirring and mixing of materials are realized, the uniformity of the components of the finished product and the physical properties are greatly improved, the problem of insufficient mixing of the traditional screw is solved, the precision gap cooperation between the barrel and the screw is realized, the quantitative stable pressure extrusion design is combined, the continuity and stability of plastic extrusion are ensured, the defects such as bubbles and material shortage of the finished product are reduced, and the qualified rate of the formed product is improved.

Description

Technical Field

[0001] This invention relates to the field of mixing and extrusion equipment, and more particularly to a multi-screw synchronous spiral multi-mixing mill barrel screw. Background Technology

[0002] As the core functional component of an extruder, the screw plays an indispensable role in the extrusion molding of materials such as plastics and rubber. It directly undertakes key tasks such as material conveying, melting, mixing and extrusion molding. Its structural design and performance directly determine the quality precision of the finished product, production efficiency and the applicability of the equipment.

[0003] Currently, most traditional plastic extrusion machine screws on the market adopt a single-screw or simple twin-screw design with a relatively fixed function, which has obvious limitations in actual production applications: These screws generally rely on a single helical propulsion to achieve material mixing, with limited stirring dimensions. For multi-component, high-viscosity, or highly filled materials, it is difficult to achieve sufficient shearing and homogenization effects, which can easily lead to uneven composition and deviations in physical properties of the finished product. At the same time, in order to ensure basic mixing and conveying effects, traditional screws need to be designed with a long stroke, which significantly increases the floor space of the entire extrusion production line, increasing the investment in plant infrastructure and space utilization costs. In addition, the fixed diameter of traditional screws makes them poorly adaptable to different forms of materials such as granules and powders, making it difficult to meet the processing needs of diverse extruded products. Moreover, traditional barrels are mostly integral structures, requiring complete disassembly for later maintenance or replacement of vulnerable parts, which is cumbersome and costly to maintain. At the same time, their simple exhaust structure design makes it difficult to effectively remove gases and volatiles generated during material processing, which can easily lead to defects such as bubbles and pinholes in the finished product, affecting molding stability and yield. Summary of the Invention

[0004] To overcome the above shortcomings, the present invention provides a multi-screw synchronous spiral multi-mixing mill screw, which aims to improve the problem of insufficient mixing in existing traditional screws.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a multi-screw synchronous spiral multi-mixing mill barrel screw, comprising a feed inlet, a natural vent, a vacuum vent, a discharge outlet, a gearbox reducer, and a barrel component. The barrel component has a single hole at the feed end and four holes at the discharge end. An internal transmission unit is provided to drive multiple small screws around the circumference. The feed inlet, natural vent, vacuum vent, and discharge outlet are distributed axially along the barrel component. The inner diameter of the barrel varies with the outer diameter of the mating screws, forming a precise clearance. The screw assembly includes a single screw in the feeding section and two or more circumferentially distributed small screws. The single screw in the feeding section has an enlarged outer diameter and a shortened stroke. The small screws are inserted and fixed in the screw grooves of the single screw in the feeding section and are driven to rotate synchronously by a gearbox reducer. Each small screw is equipped with at least one set of mixing units. The gearbox reducer is connected to the screw assembly for driving the single screw in the feeding section to drive the circumferential small screws to rotate together, thereby achieving quantitative and stable pressure extrusion molding of the material.

[0006] Furthermore, the single screw and multiple small screws in the feeding section are integrally or segmentally fixedly connected.

[0007] Furthermore, the mixing unit is a raised stirring structure, which is spaced apart along the axial direction of the small screw.

[0008] Furthermore, the barrel component is a segmented design, with each segment being detachably connected via flanges or clips.

[0009] Furthermore, the discharge port has a porous structure, and the number of holes is matched with the number of small screws distributed around the circumference.

[0010] Furthermore, the outer diameter of the small screw is smaller than the outer diameter of the single screw in the feeding section, and the pitch is matched with the pitch of the single screw in the feeding section.

[0011] Furthermore, the output shaft of the gearbox reducer is fixedly connected to one end of the single screw in the feeding section, and multiple small screws are driven to rotate synchronously through bevel gears or synchronous belts.

[0012] Furthermore, the inner wall of the barrel component is provided with a wear-resistant coating, and the screw component is made of a high-temperature resistant alloy material.

[0013] The present invention has the following beneficial effects: 1. In this invention, a composite structure of a single screw in the feeding section and multiple small screws distributed around the circumference is adopted. Combined with various mixing units on the small screws, the material is mixed in multiple dimensions, which greatly improves the uniformity of the finished product composition and physical properties. This solves the problem of insufficient mixing in traditional screws. The barrel and screw outer diameters are precisely matched. Combined with the quantitative and pressure-stabilized extrusion design, the continuity and stability of plastic extrusion are ensured, defects such as bubbles and material shortages in the finished product are reduced, and the qualification rate of molded products is improved.

[0014] 2. In this invention, the combination design of large and small screw diameters is suitable for various material shapes such as granules and powders, which can meet the processing needs of more types of extruded products. It breaks through the limitation of traditional screws being applicable to only one type of material. The differentiated design of single hole at the feed end and multiple holes at the discharge end of the barrel, combined with the multi-screw synchronous rotating structure, can not only adapt to the needs of batch production, but also flexibly adjust the processing parameters to adapt to the molding requirements of different specifications of products. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the main structure of a multi-screw synchronous spiral multi-mixing mill barrel screw proposed in this invention; Figure 2 This is a plan view of a multi-screw synchronous spiral multi-mixing mill barrel screw proposed in this invention; Figure 3 This is a cross-sectional schematic diagram of a multi-screw synchronous spiral multi-mixing mill barrel screw proposed in this invention; Figure 4 This is a schematic diagram of the discharge port structure of a multi-screw synchronous spiral multi-mixing mill screw proposed in this invention.

[0016] Legend: 1. Feed inlet; 2. Natural exhaust outlet; 3. Vacuum exhaust outlet; 4. Discharge outlet; 5. Gearbox reducer. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Reference Figures 1-4One embodiment of the present invention provides a multi-screw synchronous spiral multi-mixing mill barrel screw, including a feed inlet 1, a natural vent 2, a vacuum vent 3, a discharge outlet 4, a gearbox reducer 5, and a barrel assembly. The barrel assembly has a single hole at the feed end and four holes at the discharge end. An internal transmission unit is provided to drive multiple small screws around the circumference. The feed inlet 1, natural vent 2, vacuum vent 3, and discharge outlet 4 are distributed along the axial direction of the barrel assembly. The inner diameter of the barrel varies with the outer diameter of the mating screws to form a precision... Clearance; Screw assembly, the screw assembly includes a single screw in the feeding section and two or more circumferentially distributed small screws. The outer diameter of the single screw in the feeding section is increased and the stroke is shortened. The multiple small screws are inserted and fixed in the screw groove of the single screw in the feeding section. They are driven to rotate synchronously by a gearbox reducer 5. At least one set of mixing units is provided on the small screws. The gearbox reducer 5 is connected to the screw assembly for driving the single screw in the feeding section to drive the circumferential small screws to rotate together, so as to realize quantitative and stable pressure extrusion molding of materials. Specifically, after the material enters the barrel through the feed inlet 1, it directly contacts the single screw of the feed section with a large outer diameter and short stroke. This structure significantly improves the feeding efficiency by increasing the contact area between the screw and the material and shortening the initial conveying path. At the same time, the screw's helix angle and the barrel form a precise clearance fit, which produces a preliminary compaction effect on the material, avoiding the loose material and uneven mixing in the subsequent mixing stage, and laying the foundation for the rapid advancement of high-viscosity materials.

[0019] The gearbox reducer 5 is rigidly connected to the single screw in the feeding section via the output shaft. After starting, it drives the single screw to rotate at a constant speed. At the same time, the bevel gear or synchronous belt drive unit in the barrel transmits power synchronously to multiple small screws inserted in the screw groove of the single screw, realizing zero-differential synchronous rotation of the main screw and multiple small screws. The core advantage of this design is to avoid the problem of excessive or insufficient local shearing of materials caused by the speed difference in traditional multi-screw systems. This makes the shearing and mixing intensity of the material more uniform throughout the entire stroke, thus improving the stability of the mixing process.

[0020] As the material is propelled into the mixing section by the screw, the raised mixing unit on the small screw generates a combined effect of repeated kneading and radial shearing on the material. The irregular contour of the mixing unit and the gap between it and the inner wall of the barrel significantly improve the melting and dispersion of the material. At the same time, the pitch matching design of the main screw and the small screw enables the material to form an axial pushing and circumferential stirring flow trajectory during the propulsion process, which greatly reduces the agglomeration of highly filled materials.

[0021] During this stage, the natural exhaust port 2 will discharge the atmospheric pressure air released after the material is heated, preventing air bubbles from remaining; the vacuum exhaust port 3 will use the vacuum environment to remove low-boiling-point volatiles from the material, such as small molecule additives and moisture, ultimately controlling the volatile content of the material to below 0.5%, significantly improving the mechanical properties and surface finish of the finished product.

[0022] After being mixed in multiple stages, the material is continuously pushed by the synchronously rotating screw, forming a stable back pressure environment at the end of the barrel. The pressure fluctuation is controlled within ±0.2MPa. Finally, the material is discharged through the multi-hole outlet 4, which is adapted to the number of small screws. The multi-hole structure can concentrate and disperse the pressure of single-hole extrusion into multiple channels for uniform discharge. This not only reduces the risk of wear at the end of the barrel, but also controls the cross-sectional size deviation of the extruded material within ±0.1mm, meeting the molding accuracy requirements of precision profiles, modified particles and other products.

[0023] The entire process, through the coordinated design of structure and power transmission, not only shortens the total stroke of material from feeding to extrusion, but also achieves the dual goals of efficient processing of high-viscosity or multi-component materials and output of finished products with low volatile content or high uniformity through the combined effect of multi-screw synchronous strong mixing and staged degassing.

[0024] Working principle: Material enters through the feed inlet 1 of the barrel component and is received by the single screw in the feeding section. This single screw adopts a design with an increased outer diameter and a shortened stroke, which can improve feeding efficiency and quickly push the material into the barrel to prepare for subsequent mixing. After the gearbox reducer 5 starts, it drives the single screw in the feeding section to rotate. At the same time, the transmission unit inside the barrel drives multiple small screws distributed circumferentially to rotate synchronously. The small screws are inserted and fixed in the screw groove of the single screw to ensure consistent rotation rhythm, forming a transmission mode in which the main screw drives and multiple small screws cooperate. The material moves forward under the spiral propulsion of the main screw and the small screw. The mixing unit on the small screw repeatedly stirs and shears the material. At the same time, the precise gap between the barrel and the screw creates an extrusion effect, realizing the melting, homogenization and modification of the material. During the process, the natural exhaust port 2 discharges the atmospheric pressure gas in the material, and the vacuum exhaust port 3 removes low-pressure volatiles, further improving the purity of the material. After multi-stage mixing, the material forms a stable pressure under the push of the synchronously rotating screw, and finally is quantitatively extruded through the porous structure of the barrel outlet 4 to complete the molding process.

[0025] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-screw synchronous spiral multi-mixing mill barrel screw, comprising a feed inlet (1), a natural vent (2), a vacuum vent (3), a discharge outlet (4), and a gearbox reducer (5), characterized in that, Also includes: The barrel component has a single hole at the feed end and four holes at the discharge end. It is equipped with a transmission unit that drives multiple small screws around the circumference. The feed port (1), natural exhaust port (2), vacuum exhaust port (3), and discharge port (4) are distributed along the axial direction of the barrel component. The inner diameter of the barrel changes with the outer diameter of the screw and forms a precision gap. The screw assembly includes a single screw in the feed section and two or more circumferentially distributed small screws. The outer diameter of the single screw in the feed section is increased and the stroke is shortened. The multiple small screws are inserted and fixed in the screw groove of the single screw in the feed section and are driven to rotate synchronously by a gearbox reducer (5). At least one set of mixing units is provided on the small screw. The gearbox reducer (5) is connected to the screw component for transmission, and is used to drive the single screw in the feeding section to drive the small screw in the circumference to rotate together, so as to realize the quantitative and stable pressure extrusion molding of the material.

2. The multi-screw synchronous spiral multi-mixing mill barrel screw according to claim 1, characterized in that: The feeding section's single screw and multiple small screws are integrated or segmented fixedly connected structures.

3. The multi-screw synchronous spiral multi-mixing mill barrel screw according to claim 1, characterized in that: The mixing unit is a raised stirring structure, which is spaced apart along the axial direction of the small screw.

4. The multi-screw synchronous spiral multi-mixing mill barrel screw according to claim 1, characterized in that: The barrel component is a segmented design, and the segments are detachably connected by flanges or clips.

5. The multi-screw synchronous spiral multi-mixing mill barrel screw according to claim 1, characterized in that: The discharge port (4) has a porous structure, and the number of holes is matched with the number of small screws distributed around the circumference.

6. The multi-screw synchronous spiral multi-mixing mill barrel screw according to claim 1, characterized in that: The outer diameter of the small screw is smaller than the outer diameter of the single screw in the feeding section, and the pitch is matched with the pitch of the single screw in the feeding section.

7. The multi-screw synchronous spiral multi-mixing mill barrel screw according to claim 1, characterized in that: The output shaft of the gearbox reducer (5) is fixedly connected to one end of the single screw in the feeding section, and drives multiple small screws to rotate synchronously through bevel gears or synchronous belts.

8. The multi-screw synchronous spiral multi-mixing mill barrel screw according to claim 1, characterized in that: The inner wall of the barrel component is provided with a wear-resistant coating, and the screw component is made of high-temperature resistant alloy material.

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