Shear-Driven Microfluidic Pump Actuator Design

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Solution Overview

Problem

Existing micro-fluidic pumps are unreliable, expensive, and inefficient, with many moving components prone to failure and requiring strong electrostatic forces that are difficult to generate at small scales, making them unsuitable for small-scale heat exchange systems.

Innovation Solution

The shear-driven micro-fluidic pump (SDMFP) uses a piston with small lumens to produce high pressures and flow rates through non-harmonic actuator motion, driven by a micro-solenoid or piezo-transducer, and can include microvalves for enhanced performance, allowing for efficient fluid pumping on millimeter and sub-millimeter scales.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If existing micro-fluidic pumps use strong electrostatic forces to pump fluid, then pumping capability is achieved, but reliability deteriorates due to many moving components prone to breaking

Engineering Contradiction:
Improvepumping capabilityVSAvoidreliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent removes microvalves and other complex moving components from the micro-fluidic pump system, extracting only the essential pumping function. The pump uses a simple channel structure where fluid is moved by pressure gradients created by inlet/outlet configurations, eliminating breakable microvalves while maintaining pumping capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces complex mechanical micro-valve systems with a simplified pressure-driven flow system. Instead of using mechanical components to control flow, the design relies on pressure differentials and channel geometry to achieve fluid transport, significantly improving reliability

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

2Ease of operation

If existing micro-fluidic pumps use complex microvalves to control flow, then flow control is improved, but device complexity increases with many moving components

Engineering Contradiction:
Improveflow controlVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts and removes microvalves from the system entirely, achieving flow control through simpler means. The channel design and pressure gradient management provide sufficient flow control without requiring additional moving components or complex valve mechanisms

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pump system uses self-regulating pressure gradients and channel geometry to control flow automatically. The inlet and outlet configurations create natural pressure differentials that drive fluid movement without requiring external control mechanisms or complex valve systems

Inventive Principle:
Principle #25Self-service

3Volume of moving object

If existing micro-fluidic pumps are designed for small scale operation, then size is reduced, but manufacturing cost increases due to precision requirements

Engineering Contradiction:
Improvepump sizeVSAvoidmanufacturing cost
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent divides the micro-fluidic system into simple, modular channel segments that can be manufactured using standard micro-fabrication techniques. The channel structure is segmented into inlet regions, outlet regions, and transport paths, each optimized for its function but all manufacturable with conventional processes, reducing overall cost

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent optimizes channel dimensions and geometric parameters to achieve small scale operation while maintaining manufacturability. By carefully selecting channel widths, lengths, and cross-sectional areas, the design achieves miniaturization without requiring exotic or expensive manufacturing processes

Inventive Principle:
Principle #35Parameter changes

4Volume of moving object

If existing micro-fluidic pumps operate at small scales, then miniaturization is achieved, but efficiency deteriorates with large leakage flows and high power consumption

Engineering Contradiction:
Improvepump sizeVSAvoidefficiency
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The patent employs dynamic pressure gradient management to optimize fluid transport efficiency at small scales. The channel geometry and inlet/outlet configurations are designed to maintain favorable pressure gradients throughout operation, minimizing leakage flows and reducing the power required to drive fluid through the micro-channels

Inventive Principle:
Principle #15Dynamics

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 SDMFP is more cost-effective, robust, and reliable than existing micro-fluidic systems, offering improved efficiency, ease of manufacturing, and flexibility in size, making it suitable for various MEMS and biomedical applications with reduced leakage and energy consumption.

Implementation Method 1

Motion can be imparted onto the pump by a micro-solenoid or a piezo-transducer

Methodology Applied
Scientific EffectSolenoid: Solenoid

Implementation Method 2

Motion can be imparted onto the pump by a micro-solenoid or a piezo-transducer

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

A working principle behind a SDMFP can be the viscous diffusion of vorticity. Such vorticity can be created at the moving wall in order to satisfy the no-slip condition. Vorticity can be diffused into the fluid through the mesoscopic phenomenological momentum transport coefficient, i.e., viscosity

Methodology Applied
Scientific EffectViscous diffusion of vorticity: Diffusion

Implementation Method 4

Such vorticity can be created at the moving wall in order to satisfy the no-slip condition

Methodology Applied
Scientific EffectNo-slip condition: Boundary Layer

Data Source

PatentEP2772648B1Shear driven micro-fluidic pump
Publication Date: 2018.04.11 AAR AEROSPACE CONSULTING L L C
  • EP2772648B1 patent drawingFigure 1
  • EP2772648B1 patent drawingFigure 2A~2B
  • EP2772648B1 patent drawingFigure 3

AI summary

An apparatus to pump a fluid includes a housing (106) extending along an elongated interior (118), an actuator (102) in the housing (106), conforming to the elongated interior (118), the actuator (102) including a plurality of lumens (120), each extending substantially parallel to the elongated interior (118), each from around 10 to 200 micrometers across, and an actuator drive (104) configured to oscillate the actuator (102) in the actuator housing (106) along the elongated interior (118) with a rate differential between movement in a first direction (112) versus movement in a second direction (114) opposite the first direction to pump the fluid.