Acoustic Fluid Ejector Design to Prevent Particle Aggregation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Particle aggregation in acoustic wave-driven fluid ejectors, particularly at pressure maxima and minima, leads to inefficient ejection of particles such as biological cells and potential device clogging.
Innovation Solution
Implementing frequency sweep excitation, increasing nozzle density, using acoustically transparent materials, and adjusting the acoustic field modes to prevent particle aggregation by enhancing flow drag forces over acoustophoretic forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acoustic radiation pressure is used to separate droplets or generate jets from fluid reservoir surface, then ejection efficiency is improved, but particle aggregation at pressure maxima and minima occurs causing clogging
Solution Approach 1:
The patent applies dynamics by transitioning from static standing wave patterns to transient acoustic fields. The acoustic field is continuously modulated in time, creating moving pressure nodes and maxima that prevent particles from settling at fixed aggregation points. This temporal dynamics disrupts the formation of stable aggregation zones while maintaining ejection forces.
Solution Approach 2:
The patent employs periodic action through pulsed or modulated acoustic excitation. By applying acoustic energy in periodic bursts rather than continuous steady-state waves, the system creates alternating phases of particle ejection and field reset. This periodic modulation prevents sustained particle aggregation at pressure extrema while maintaining high ejection efficiency during active phases.
2Use of energy by moving object
If standing wave patterns are formed in fluid reservoir, then high pressure levels for ejection are generated with low input energy, but particle collection at pressure maxima and minima increases aggregation
Solution Approach 1:
The patent transforms the static energy distribution of standing waves into a dynamic transient field. Energy is delivered in controlled pulses that create moving pressure patterns rather than stationary nodes. This allows the system to achieve effective particle ejection with lower sustained energy input, as the transient nature prevents energy from being continuously trapped in aggregation-prone standing wave patterns.
Solution Approach 2:
The patent converts the potentially harmful effect of pressure maxima (which cause aggregation) into a beneficial transient ejection force. By using short-duration acoustic pulses, the pressure maxima briefly accelerate particles toward ejection points before the field collapses, preventing aggregation while maintaining ejection efficiency. The harmful standing wave pattern is transformed into a useful transient impulse.
3Force
If acoustophoretic forces are used to move particles, then particle separation is achieved, but flow drag forces are insufficient to overcome aggregation at pressure nodes
Solution Approach 1:
The patent applies dynamics by creating transient acoustic fields where pressure nodes and maxima move through the fluid rather than remaining stationary. This movement continuously redistributes particles, preventing them from settling at fixed aggregation points. The dynamic field ensures that acoustophoretic forces consistently drive particles toward ejection points without allowing flow drag to become insufficient at any fixed location.
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
Enhances particle ejection efficiency by minimizing aggregation, ensuring consistent fluid flow, and preventing device clogging, thereby improving overall recovery and operation reliability.
Implementation Method 1
Some of these ejectors would utilize acoustic radiation pressure to separate droplets or generate jets from a surface of a fluid reservoir
Implementation Method 2
an acoustic wave actuator in connection with a fluid reservoir can generate acoustic fields in the reservoir which can be focused by some tapered nozzle structure with an orifice at its end
Implementation Method 3
During the operation of these acoustic ejectors, especially the ones which utilize substantially closed cavities as reservoirs and solid nozzles, or vibrating plates, acoustic waves can form standing wave patterns (pressure maxima and minima) in the fluid reservoir volume
Implementation Method 4
these particles can be collected and aggregated in pressure maxima and minima due to the acoustophoretic forces generated by the pressure field in the fluid reservoir
Implementation Method 5
administering to a sample in need thereof a standing acoustic field comprising a frequency sweep excitation to eject particles during the sweep while not allowing a clear standing aggregation to develop
Implementation Method 6
administering to a sample in need thereof a standing acoustic field having a frequency of operation capable of being switched between multiple modes of operation... the first mode and a second mode, and are capable of moving the nodal points whereas, the amplitude is such that ejection of particles happens as a result of the first mode (i.e. an ejection mode) and the second mode keeps particles in the sample in need thereof moving (i.e. a moving or mixing mode)
Data Source
AI summary
In some embodiments according to the present disclosure, methods for mitigating particle retention are provided including the use of frequency sweep excitation to eject particle in the sweep. In some embodiments according to the present disclosure, the acoustically driven fluid ejector can be capable of being switched between multiple modes of operation. In other embodiments according to the present disclosure, the acoustically driven fluid ejector can be altered such that it includes the capability to be filled with a biocompatible material to aid in the mitigation of particle aggregation in the acoustically driven fluid ejector. In some embodiments according to the present disclosure, the solid structure and number of nozzles of the acoustically driven fluid ejector can be adjusted such that the ejector of the acoustically driven fluid ejector can be self-pumping, i.e. no external pumping mechanism other than acoustics driven flow drag is used.