Fiber Separation via Acoustic Cavitation in Composite Recycling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for recycling fibers from composite materials, such as paper products with multiple layers, are inefficient due to long treatment times, which lead to fiber damage, reduced quality, and increased energy consumption, making it difficult to separate fibers from non-fiber materials like plastic and aluminum.
Innovation Solution
A cavitation-based method using a container with a vacuum system to create rapid pressure changes, allowing gas bubbles to implode and generate kinetic energy that separates fibers from composite materials without damaging them, thereby reducing treatment time and improving fiber quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wetting and steeping methods are used to separate fibers from composite materials, then fiber separation is achieved, but treatment time becomes excessively long and fiber quality deteriorates
Solution Approach 1:
The patent replaces conventional mechanical mixing and steeping systems with an acoustic field system. A sound generator emits acoustic waves into the pulp suspension, creating cavitation bubbles that implode to mechanically separate fibers from composite materials. This acoustic-based mechanism achieves separation without prolonged mechanical agitation, reducing treatment time while maintaining fiber quality.
Solution Approach 2:
The patent utilizes the phase transition of water during cavitation. Acoustic waves create pressure variations that cause water to form vapor bubbles (phase change from liquid to gas) which then collapse back to liquid. This phase transition generates intense localized mechanical forces that separate fibers efficiently, achieving the desired separation in shorter time without damaging fiber properties.
2Manufacturing precision
If prolonged mechanical mixing is applied to separate fibers, then fiber composite separation is achieved, but energy consumption increases significantly
Solution Approach 1:
The patent replaces energy-intensive mechanical mixing systems with an acoustic field system. The sound generator creates cavitation bubbles through acoustic waves, and the implosion of these bubbles provides the mechanical force needed for separation. This acoustic-based approach consumes significantly less energy than conventional mechanical mixers while achieving the same separation quality.
Solution Approach 2:
The cavitation process is self-generating in that the acoustic waves create bubbles that then generate their own mechanical force through implosion. The system uses the energy of the acoustic field to create the separating mechanism, rather than requiring continuous high-energy mechanical input. The cavitation bubbles themselves become the source of separation force, reducing overall energy requirements.
3Manufacturing precision
If extended steeping time is used for fiber separation, then complete separation is achieved, but fiber damage and quality reduction occur
Solution Approach 1:
The patent replaces prolonged mechanical steeping with acoustic cavitation. The cavitation bubbles implode with intense localized force that separates fibers from composite materials without the continuous mechanical stress that damages fibers during extended steeping. This achieves complete separation while preserving fiber strength and quality.
Solution Approach 2:
The acoustic field applies periodic oscillations at specific frequencies that resonate with the fiber-composite structure. This periodic action enhances the separation effect by creating rhythmic stress that facilitates detachment, achieving complete separation in shorter time without the continuous mechanical stress that would damage fibers.
4Productivity
If conventional pulping methods are used, then fiber processing is achieved, but additional processing steps are required for reject separation
Solution Approach 1:
The acoustic cavitation process creates distinct separation between fibers and non-fiber materials (rejects) based on their different responses to acoustic fields and cavitation forces. This results in better initial separation that reduces the burden on downstream sorting equipment, allowing for simpler additional processing steps while maintaining high productivity.
Data Source
AI summary
A method for separating fibers using a container, a vacuum pump which is connected to the container volume via a vacuum valve, and a ventilation line with a cross-sectional opening and a valve. The valve can be switched between a closed and open state in a time domain of 19-41 ms and from the open state into the closed state in a time domain of 20 to 45 ms. The method has the steps of filling the container with water and fiber composite, closing the container, mixing the water and the fiber composite using mechanical energy, by stirring, generating kinetic energy in the fiber composite by lowering the container internal pressure to a value between −700 to −950 hPa, and equalizing the pressure in the container to generate cavitation in the fiber composite. The pressure equalization taking place within at least onetime domain of 0.001-1 s.