Offset Screw Feed Layout for Stable Plastic Extruder Filling
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Solution Overview
Problem
Existing single-shaft shredders for thermoplastics face challenges in achieving efficient and stable extrusion due to unfavorable material feeding and unstable filling levels in the extruder, leading to inefficient operation and large system sizes at higher throughputs.
Innovation Solution
The central longitudinal axis of the screw is oriented at an angle (80° to 100°, preferably 90°) to the extruder screw axis, with an offset, allowing lateral material conveyance into the extruder, ensuring compact device size and stable extruder filling by utilizing the screw's density difference and a conical transition for precompression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-shaft shredder with integrated extruder is used for higher throughputs, then processing capacity increases, but device size becomes very large and operation becomes difficult
Solution Approach 1:
The patent applies dimensional change by orienting the screw's central longitudinal axis at an angle (80° to 100°, preferably 90°) to the extruder screw's central longitudinal axis, with the screw axis offset in the direction of extruder screw rotation. This angular and offset arrangement allows material to be conveyed laterally into the extruder, enabling compact device configuration even at higher throughput rates while maintaining efficient operation
2Device complexity
If material is fed directly into the extruder without proper conveying mechanism, then device simplicity increases, but extruder filling becomes unstable and extrusion quality decreases
Solution Approach 1:
The patent introduces a screw as an intermediary conveying element between the shredding unit and the extruder. This screw conveys and compresses the shredded material laterally into the extruder, ensuring stable and sufficient filling levels. The offset arrangement of the screw axis creates space for material deflection and utilizes density differences to press material against the extruder screw's active flank, providing reliable extrusion conditions
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
This configuration enables efficient and high-quality extrusion by stabilizing the extruder filling, accommodating higher throughputs, and maintaining a compact system design.
Implementation Method 1
the longitudinal axis of the screw is offset with respect to the longitudinal axis of the extruder screw by the offset (v), as depicted in FIG. 3, in the direction of the direction of rotation of the extruder screw
Implementation Method 2
A screw always has a higher density on the active flank than on the passive flank, especially when the material has not yet melted and the screw is partially filled
Implementation Method 3
These particles are further compressed in the mostly conical part and partially further heated. A part of these thermoplastic particles soften in the process.
Implementation Method 4
These particles are further compressed in the mostly conical part and partially further heated
Implementation Method 5
An extruder then follows on the same axis, further compressing and heating these particles and converting them to a liquid state.
Data Source
AI summary
Disclosed is a device for processing plastic materials, having a shredding unit, a conveying unit having a screw (7), and an extruder, having at least one extruder screw (11), adjoining the screw, wherein the central longitudinal axis (3) of the screw (7) is oriented at an angle to the central longitudinal axis (10) of the extruder screw (11), in particular at an angle of 80° to 100°, preferably 90°, and the longitudinal axis (3) of the screw (7) is offset with respect to the longitudinal axis (10) of the extruder screw (11) by an offset (v) in the direction of the direction of rotation (12) of the extruder screw (11) at or in the region of the discharge opening (8) or the intake opening (16) of the conveying unit.