Asymmetric Stirring Device for Plastic Chip Cleaning
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Solution Overview
Problem
Current methods for cleaning plastic shreds during recycling are inefficient in removing foreign matter and contamination, particularly from PET packaging, which limits their reuse in food-grade applications, and require optimal settings of temperature, mechanical treatment, cleaning liquid concentration, and residence time to achieve effective cleaning.
Innovation Solution
A device with a rotating stirring body and container having varying cross-sectional distances from the axis of rotation, enhancing mechanical cleaning through periodic pressure and relaxation areas, which increases friction between plastic chips and the device surfaces, allowing for improved abrasive cleaning without excessive use of cleaning liquids or heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning methods are used with standard stirring devices, then cleaning process is simple, but cleaning effectiveness is insufficient for food-grade recycling
Solution Approach 1:
The stirring device employs an asymmetric cross-sectional design where the distance between the rotating body and container wall varies around the circumference. This asymmetric geometry creates non-uniform flow patterns and enhanced mechanical action on the plastic chips, significantly improving cleaning effectiveness compared to conventional symmetric stirring devices.
Solution Approach 2:
The stirring device creates dynamic cleaning conditions through rotational motion that continuously changes the distance between the rotating body and container wall. This dynamic variation in geometry produces changing flow patterns and mechanical forces during rotation, enhancing the cleaning action on plastic chip surfaces.
2Manufacturing precision
If mechanical treatment is increased to improve cleaning, then cleaning effectiveness improves, but energy consumption and friction increase
Solution Approach 1:
The cleaning process is segmented into multiple phases within a single rotating device, creating alternating regions of high mechanical action and lower resistance. The varying cross-sectional geometry divides the cleaning path into segments that exploit different mechanical effects, improving overall cleaning efficiency while distributing energy consumption more effectively.
Solution Approach 2:
The varying cross-sectional design creates periodic variations in mechanical action during rotation. As the rotating body passes through different radial positions, it generates periodic cycles of compression and relaxation, enhancing cleaning through repeated mechanical action while allowing energy recovery during lower-resistance phases of the rotation cycle.
3Manufacturing precision
If residence time is extended to improve cleaning, then cleaning effectiveness improves, but productivity decreases
Solution Approach 1:
The stirring device maintains continuous and intensive cleaning action throughout the residence period through its varying cross-sectional design. The asymmetric geometry ensures that plastic chips are constantly subjected to effective mechanical cleaning forces without idle periods, maximizing cleaning efficiency per unit time and enabling shorter residence times for the same cleaning quality.
Solution Approach 2:
The cleaning action combines multiple mechanisms within a single device: mechanical friction, compression, and flow-induced cleaning. This composite cleaning approach achieves superior cleaning effectiveness through the synergistic combination of different physical effects, reducing the residence time needed compared to single-mechanism cleaning methods.
4Manufacturing precision
If cleaning liquid concentration is increased to improve cleaning, then cleaning effectiveness improves, but environmental impact and cost increase
Solution Approach 1:
The invention replaces chemical cleaning mechanisms with enhanced mechanical cleaning action through the asymmetric stirring device. The varying cross-sectional geometry generates sufficient mechanical friction and compression to remove contaminants without requiring high concentrations of cleaning liquids, thereby reducing environmental impact and operational costs associated with chemical disposal.
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 device achieves enhanced mechanical cleaning efficiency, effectively removing contaminants and adhesives, enabling the reuse of recycled plastic in food-grade applications with reduced operational costs and environmental impact.
Implementation Method 1
The mechanical component leads to friction or Friction either of the plastic shreds among themselves and/or for friction or friction of the plastic shreds on the surfaces of the respective device
Implementation Method 2
Good cleaning of the plastic shreds can only be achieved by optimally setting these four parameters... the proportion of mechanical cleaning must be increased
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Device (1) for cleaning the plastic chips, comprises a container (2) for receiving the plastic chips and an agitator (4) rotatably mounted in the container about a rotational axis (400) for stirring the plastic chips, where agitator comprises a rotary body (5) extending along the rotational axis. The rotary body has a cross-section perpendicular to the rotational axis, which varies the distance (a) from the rotational axis. An independent claim is also included for cleaning the plastic chips, comprising introducing the plastic chips into a container in which agitator is provided for stirring the plastic chips, applying a compression to the plastic chips, which changes in the time course for rotating the rotary body about the rotational axis.