CN-122008519-A - Low-shear high-efficiency mixed double-screw assembly and application thereof

Abstract

The invention relates to a low-shear high-efficiency mixed double-screw assembly and application thereof, wherein the double-screw assembly comprises a cylinder body and two screws meshed in the same direction, grooves are formed in screw edges of the screws along the axial direction, and a radial gap between the two screws is 0.45-0.75 mm. According to the invention, the low-shear macroscopic flow channel and the high-efficiency particle distribution structure are constructed through the cooperation of the screw edge axial grooves and the radial gaps, so that the technical problem that the high mixing efficiency of the traditional double-screw assembly depends on high shear is effectively solved, and the invention can be widely applied to the mixing processing of the fields of high polymer materials, bioactive materials and the like, and has outstanding practical value and popularization prospect.

Inventors

• WANG HAOLIANG
• Di Chuanjun
• CHENG JINGCAI
• YANG LI
• CHEN SHILONG
• ZHENG YAOMIN
• YANG CHAO

Assignees

• 中国科学院过程工程研究所

Dates

Publication Date

20260512

Application Date

20260202

Claims (10)

1. 1. The utility model provides a high-efficient mixed twin-screw subassembly of low shear, its characterized in that, twin-screw subassembly includes barrel and two syntropy meshing screw rods, open along the axial on the arris of screw rod has the recess, radial clearance between two screw rods is 0.45~0.75mm.
2. 2. The twin screw assembly defined in claim 1, wherein the gap between the screws and the barrel is the same as the radial gap between the two screws.
3. 3. The twin screw assembly defined in claim 1 or claim 2, wherein the grooves comprise double circular arc grooves formed by a combination of two circular arcs of the same radius of curvature; preferably, the depth of the groove is 0.48-0.58 of the height of the screw flight.
4. 4. A twin-screw assembly according to claim 3, wherein the radius of curvature of the circular arc is 4.55-4.75 mm.
5. 5. A twin-screw assembly as defined in claim 3, in which the circumferentially spaced apart angles of the two circular arc centers of the double circular arc groove are 9.2-10.8 °.
6. 6. The double-screw assembly according to any one of claims 1-5, wherein each turn of the screw flight is provided with 6-8 grooves, and the grooves are uniformly distributed along the circumferential direction of the screw; preferably, the grooves are arranged in a reverse spiral mode, and the spiral angle of the reverse spiral is 1.2-1.8 degrees.
7. 7. The twin-screw assembly defined in any one of claims 1-6, wherein the grooves of adjacent turns of the flighting are in aligned distribution.
8. 8. The twin-screw assembly defined in any one of claims 1-7, wherein the screw flight has a peripheral diameter of 34.5-35.1 mm and the screw groove bottom has a diameter of 23.50-24.00 mm.
9. 9. Use of a twin screw assembly according to any one of claims 1 to 8, wherein the use comprises the use of the twin screw assembly for the transportation and mixing of high solids content heat sensitive materials.
10. 10. The use according to claim 9, wherein the high solids content heat sensitive material has a solids content of 40 to 65vol%, the high solids content heat sensitive material comprising any one of a solid propellant, a solid battery electrode paste or a highly filled thermoplastic.

Description

Low-shear high-efficiency mixed double-screw assembly and application thereof Technical Field The invention relates to the technical field of high polymer material processing machinery, in particular to a low-shear high-efficiency mixed double-screw assembly and application thereof. Background In the processing of high molecular materials, the safe delivery of high solids content sensitive materials such as solid propellants, solid battery electrode pastes, highly filled thermoplastics, and the like, which materials typically have extremely high viscosity and shear heat sensitive properties, has been a serious challenge. The traditional homodromous meshing double-screw extruder adopts a small-gap screw element (0.1 mm-0.3 mm) and high screw rotating speed to generate high shear so as to strengthen mixing and conveying, but the design paradigm has fundamental contradiction with the processing requirement of high-solid-content sensitive materials, namely, although the small gap can establish high pressure to promote conveying, extremely high shear rate is generated at the same time, so that sensitive materials are degraded or materials are burnt and exploded. The rotation speed is reduced to protect the materials, and the conveying capacity is weakened, so that the materials are discharged or blocked. The flow and mixing of particles in non-newtonian fluids in high solids systems is extremely difficult and conventional conveying elements only have the ability to convey materials at low screw speeds, which would be a significant limitation for high viscosity, high fill systems. CN 115674638a discloses a hill-shaped stretching and mixing element, the mixing element comprises a charging barrel and a screw, at least two continuous hill-shaped structures are arranged along the screw by the hill-shaped stretching and mixing element, each hill-shaped structure is provided with a plurality of hill-shaped structures which are uniformly arranged along the axial direction, and adjacent hill-shaped structures are distributed in a staggered manner. The stretching flow field generated by the hillock stretching and mixing element can effectively lead the materials to be uniformly mixed, and the mixing and mixing effect is good. The split flow effect formed by the hillock structure can enable materials to be better dispersed and distributed, and local overheating is avoided. However, in the practical application process, the shearing action of the materials is obviously increased due to the high screw rotating speed and the small screw clearance, so that the materials are degraded and burnt, and the safe extrusion of the sensitive materials can not be ensured while the mixing effect is improved. CN 113557113a discloses a screw for an extruder or conveyor with undercut flights, the screw elements having flights helically surrounding a core, the flights being configured undercut in the conveying direction at least in one section of the screw at its active conveying side. The design of the profile of the screw flights offers advantages in terms of feed performance by the configuration of the undercut and results in efficient filling of the extruder. The undercut conveying side is particularly advantageous for light substances such as foam materials or for materials with low bulk density. However, the screw element has a limited system, can be used for conveying uniformly mixed polymers, and cannot be used for conveying and mixing a solid-liquid mixing system in an industrial production process with high efficiency. CN 120793455A discloses a conveying device for solid-liquid mixed materials, which comprises a frame, a conveying pipeline is arranged on the frame, a fixed shaft and an auger blade are arranged in the conveying pipeline, the fixed shaft is fixedly arranged in the conveying pipeline and extends along the length direction of the conveying pipeline, the auger blade coaxially rotates and is arranged outside the fixed shaft, the inner peripheral surface of the auger blade is attached to the outer peripheral surface of the fixed shaft, one end of the conveying pipeline is further provided with a driving mechanism, the driving mechanism can drive the auger blade to rotate around the fixed shaft, so that the auger blade conveys the solid-liquid mixed materials forwards from back to front, and meanwhile, the auger blade scrapes the liquid materials adhered on the fixed shaft. However, during the mixing of sensitive material systems, the shearing action exerted by the scraping device on the material is above a safety threshold. In view of the deficiencies of the prior art, there is a great need in the art for a novel screw design that synergistically optimizes the conveying, mixing and shearing history to break through the processing bottlenecks of high solids sensitive materials. Disclosure of Invention In order to solve the technical problems, the invention realizes the purposes of no material conveying dead zone, far excee