Microfluidic Filtering with Inertial Micropump Self-Cleaning

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Solution Overview

Problem

Microfiltration systems often face clogging issues due to the accumulation of particles in filter components, leading to reduced sample flow rates and increased pressure requirements, eventually rendering the filters inefficient or inoperable.

Innovation Solution

The implementation of microfluidic filtering devices with embedded inertial micropumps that enable active and passive self-cleaning functions, allowing for controlled forward and reverse fluid flows through nested filter loops to prevent and resolve clogs, maintaining filter efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If microfiltration is used to filter particles from fluid samples, then particle filtering efficiency is improved, but filter clogging occurs leading to reduced sample flow rates and increased pressure requirements

Engineering Contradiction:

Improveparticle filtering efficiencyVSAvoidsample flow rate

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent applies reverse flow through the filter loop to dislodge and remove accumulated particles from the filter component. By pumping fluid in the opposite direction through the same filter, the system inverts the normal filtration flow path, enabling particles that caused clogging to be flushed back into the main channel and removed, thus restoring sample flow rate while maintaining filtering efficiency

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The system continuously alternates between forward filtration flow and reverse cleaning flow through the filter loop, ensuring uninterrupted operation. The controller automatically switches between filtration mode and cleaning mode, maintaining continuous particle removal capability and preventing complete filter blockage, thereby sustaining both filtering efficiency and acceptable sample flow rates over extended periods

Inventive Principle:

Principle #20Continuity of useful action

2Measurement precision

If microfiltration is used to filter particles from fluid samples, then particle filtering efficiency is improved, but pressure requirements increase eventually rendering the filter inoperable

Engineering Contradiction:

Improveparticle filtering efficiencyVSAvoidpressure requirements

Core Design Contradiction:

Measurement precisionVSStress or pressure

Solution Approach 1:

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The system performs preliminary cleaning actions by periodically activating the reverse flow through the filter loop before complete clogging occurs. The controller monitors filtration performance and triggers cleaning cycles in advance, preventing the buildup of critical particle accumulation that would lead to excessive pressure requirements and filter failure

Inventive Principle:

Principle #10Preliminary action

3Productivity

If self-cleaning functions are implemented with embedded micropumps, then filter efficiency is maintained, but device complexity increases

Engineering Contradiction:

Improvefilter efficiency maintenanceVSAvoiddevice complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the cleaning function with the existing filtration system by using the same filter loop infrastructure. The reverse flow cleaning mechanism utilizes the existing pump and channel structure, combining filtration and cleaning operations into a single integrated system rather than adding separate cleaning apparatus, thus limiting the increase in device complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The filter loop serves dual functions: forward flow for particle filtration and reverse flow for self-cleaning. The same physical infrastructure (pump, channels, filter component) performs multiple operations, eliminating the need for separate dedicated cleaning systems and reducing overall device complexity despite adding self-cleaning capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enhances the speed, efficiency, and productivity of microfluidic filtering by preventing filter clogs and maintaining optimal flow rates, ensuring continuous operation.

Implementation Method 1

activating a first fluid pump within a microfluidic channel to cause a forward flow of fluid through the microfluidic channel and through a filter of a filter loop

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

activating a second fluid pump to cause a reverse flow of fluid through the filter

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3414011B1Microfluidic filtering

Publication Date: 2023.01.04 HEWLETT PACKARD DEVELOPMENT COMPANY LP

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Figure 6a~7a

AI summary

In an example implementation, a method of microfluidic filtering includes activating a first fluid pump within a microfluidic channel to cause a forward flow of fluid through the microfluidic channel and through a filter of a filter loop. The filter loop intersects the microfluidic channel at a loop entry and at a loop exit. The method includes activating a second fluid pump to cause a reverse flow of fluid through the filter.