Single-Screw Extruder Die Geometry for Heterogeneous Materials
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Solution Overview
Problem
Existing single-screw extruders struggle to efficiently process heterogeneous materials due to their density, physical state, and particle size variations, making it difficult to achieve uniform processing and conversion into raw material for further processing.
Innovation Solution
A single-screw extruder design with specific geometric relationships between the rotor member's depth and diameter, and pitch and diameter, combined with a die structure featuring a continuously circular flow channel and radial output ports, allows for efficient processing of heterogeneous materials by maintaining a low volume screw channel and controlled temperature, enabling efficient conversion into raw material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional single-screw extruders are used to process heterogeneous materials, then the extruder can operate with standard geometric parameters, but the processing efficiency and uniformity deteriorate due to density, physical state, and particle size variations
Solution Approach 1:
The patent applies parameter changes by optimizing the geometric parameters of the rotor member, specifically setting the depth-to-diameter ratio (d:D) to not more than 1:20 and the pitch-to-diameter ratio (P:D) to not more than 1:4. These parameter modifications enable the extruder to effectively process heterogeneous materials with varying density, physical state, and particle size, resolving the contradiction between processing efficiency and uniformity
Solution Approach 2:
The die structure implements local quality by providing a continuously circular flow channel in its cross-sections, with specific local features including radial openings as material output ports and blocking means at the end of the flow channel. This localized structural optimization ensures uniform material flow and processing quality despite material heterogeneity
2Quantity of substance
If the rotor member has larger cavity depth or pitch, then the volume of material processed increases, but the power consumption and temperature control difficulty increase
Solution Approach 1:
The patent resolves this contradiction by changing the geometric parameters of the rotor member to have small depth (d:D ≤ 1:20) and small pitch (P:D ≤ 1:4). This parameter optimization allows the extruder to process adequate material volume while maintaining low power consumption and effective temperature control, avoiding the energy penalties associated with larger cavity dimensions
3Manufacturing precision
If the flow channel is not continuously circular, then the die structure can be simpler, but the material flow uniformity and processing quality deteriorate
Solution Approach 1:
The patent applies spheroidality by designing the flow channel to be continuously circular in all its cross-sections. This curved, circular geometry ensures uniform material flow distribution and high processing quality. The circular form is maintained throughout the flow channel while incorporating radial openings and blocking means, achieving processing quality without excessive structural complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The extruder effectively processes heterogeneous materials, such as recycled plastics and fibers, by optimizing power usage and temperature control, facilitating efficient conversion into raw material suitable for further processing.
Implementation Method 1
a cylindrical rotor member having diameter and length and comprising a feeding zone, the rotor member arranged in a barrel, the cylindrical surface of the rotor member carrying cavity/cavities and/or projection(s) arranged in helically extending rows
Implementation Method 2
B) heating the material in said single-screw extruder to a flowable state
Implementation Method 3
the outer ring is provided with at least one radial opening as a material output port, and a blocking means for blocking the end of the flow channel after the radial opening being arranged in the die
Data Source
Figure 1a~1d
Figure 2~5
Figure 3a~3b
AI summary
A single-screw extruder (100) and method. The extruder comprises a cylindrical rotor member, the rotor member (1) arranged in a barrel (2), and a drive system (4) for the rotation of the rotor member (1) in the barrel (2). The extruder further comprises an outlet (16) of the extruder is provided with a die (23), comprising an outer ring (24) arranged to the barrel (2),an inner die part (25),the die (23) establishing a flow channel (26) that is continuously circular in all its cross-sections.