Microfluidic Valve Acoustic Flow Control

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Solution Overview

Problem

Microfluidic valves in existing systems face challenges with material compatibility, high manufacturing costs, and reduced reliability due to the presence of moving parts, which affect their ability to control fluid flow effectively in microfluidic systems.

Innovation Solution

The use of frequency-controlled inertial pumps, which are asymmetrically positioned within microfluidic channels, allows for dynamic control of fluid flow by adjusting the activation frequencies of multiple pumps to create various flow patterns, reducing pressure loss and eliminating moving parts, thereby enhancing reliability and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional valves are used in microfluidic systems, then fluid flow control is achieved, but material compatibility is limited and manufacturing costs increase

Engineering Contradiction:
Improvemanufacturing costVSAvoidvalve reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces traditional mechanical valves with moving parts with a valveless microfluidic system that uses acoustic radiation forces to control fluid flow. Acoustic standing waves created by piezoelectric actuators manipulate particles and droplets without mechanical contact, eliminating moving parts while maintaining flow control functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses acoustic waves (a form of mechanical wave propagation through fluid) to create radiation forces that manipulate fluid elements. The acoustic field acts as a non-contact actuation mechanism, using pressure nodes and antinodes to trap and move particles and droplets through the microfluidic channels.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If traditional valves with moving parts are used, then fluid flow control is achieved, but reliability is reduced

Engineering Contradiction:
Improvevalve reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical valves with moving parts with a valveless microfluidic system that uses acoustic radiation forces to control fluid flow. Acoustic standing waves created by piezoelectric actuators manipulate particles and droplets without mechanical contact, eliminating moving parts while maintaining flow control functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the fluid's own acoustic properties and the natural formation of standing waves to create self-organizing flow patterns. The acoustic radiation forces automatically trap particles at pressure nodes and move them along defined paths without requiring complex mechanical control mechanisms.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If inertial pumps are used to control fluid flow, then flow control precision is improved, but pressure loss increases

Engineering Contradiction:
Improveflow control precisionVSAvoidpressure loss
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The system uses periodic acoustic actuation to create controlled fluid flow. By applying alternating acoustic fields at specific frequencies, the system generates periodic radiation forces that propel droplets and particles through the channels in a controlled manner, enabling precise flow regulation without continuous mechanical pumping.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system exploits the phase relationship between acoustic waves and particle motion to control flow. By adjusting the phase and frequency of acoustic actuation, the system can precisely control droplet velocity and position while minimizing energy dissipation through optimized acoustic cycling.

Inventive Principle:
Principle #36Phase transitions

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 approach provides improved fluid flow control with reduced pressure loss and increased reliability by dynamically adjusting the activation frequencies of inertial pumps, allowing for precise control of fluid flow through microfluidic channels without the need for moving parts, thus addressing the limitations of existing microfluidic valve technologies.

Implementation Method 1

an acoustic radiation force to move fluid through the microfluidic channel

Methodology Applied
Scientific EffectAcoustic radiation force: Acoustic Radiation Pressure

Implementation Method 2

The inertial pump may include a piezoelectric actuator

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3180415B1Microfluidic valve
Publication Date: 2020.07.08 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3180415B1 patent drawingFigure 1~2F
  • EP3180415B1 patent drawingFigure 3~4D
  • EP3180415B1 patent drawingFigure 5~6C

AI summary

In an example implementation, a method of controlling a microfluidic valve includes activating a first inertial pump at a first frequency, and a second inertial pump at a second frequency to create a first fluid flow pattern within a microfluidic valve. The method also includes adjusting at least one of the first frequency and the second frequency to change the first fluid flow pattern to a second fluid flow pattern.