Microfluidic Filter Chamber Bubble-Free Filling

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Solution Overview

Problem

Existing microfluidic systems face challenges in bubble-free filling and clogging of filters during liquid filtration processes, leading to inefficient filtration and potential for undesired reactions due to trapped air bubbles and uneven flow.

Innovation Solution

A microfluidic filter chamber with an adjustable ventilation channel and valve system, featuring widened inlet and outlet channels with a funnel-shaped cross-section, allows for controlled liquid flow and bubble-free filling by regulating the passage of liquids and gases, preventing clogging and ensuring homogeneous flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If manual pipetting and centrifugation are used to fill filters, then the filling process is simple, but air bubbles are trapped and the filter becomes clogged

Engineering Contradiction:
Improvefilling process simplicityVSAvoidfilter clogging
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention extracts and removes air bubbles from the liquid before the liquid reaches the filter. A separate air removal channel is provided that allows air bubbles to be extracted from the liquid stream, preventing them from entering the filter and causing clogging, while the liquid continues to flow through to the filter without interruption

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The filling channel is segmented into multiple functional sections: a liquid introduction section, an air removal section with separate air and liquid channels, and a filter connection section. This segmentation allows independent control of liquid flow and air removal, enabling bubble-free filling while maintaining operational simplicity

Inventive Principle:
Principle #1Segmentation

2Productivity

If the inlet channel is narrow to maintain low fluid resistance, then fluid flow is efficient, but homogeneous flow onto the filter cannot be ensured

Engineering Contradiction:
Improvefluid flow efficiencyVSAvoidflow homogeneity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The inlet channel features an asymmetric cross-sectional design that transitions from a narrower entry section to a wider distribution section. This asymmetric geometry allows the channel to maintain lower overall resistance while creating a broader flow distribution area that ensures homogeneous liquid flow onto the filter surface

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The inlet channel transitions from a two-dimensional narrow passage to a three-dimensional expanded distribution region before reaching the filter. This dimensional transition allows the liquid flow to spread out and distribute evenly across the filter surface, achieving homogeneous flow while maintaining efficient fluid resistance through the tapered transition design

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the ventilation channel is always open to allow air escape, then bubble-free filling is achieved, but liquid flow cannot be precisely regulated

Engineering Contradiction:
Improvebubble-free fillingVSAvoidliquid flow regulation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The ventilation channel is designed with a dynamically controllable valve that can adjust its opening degree. This allows the system to switch between different operational modes: fully open for bubble-free filling, partially open for controlled venting during filtration, and closed when precise liquid flow regulation is needed. The dynamic adjustability resolves the contradiction by providing context-dependent functionality

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A valve mechanism serves as an intermediary between the ventilation channel and the liquid flow path. This intermediary component allows selective control of air escape while maintaining precise regulation of liquid flow. The valve acts as a mediator that can independently control gas and liquid phases, enabling both bubble-free filling and precise flow regulation as needed

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables precise regulation of fluid flow, prevents bubble entrapment, ensures complete rinsing, and maintains consistent fluid resistance, facilitating controlled reagent exchange and preventing foam formation, thus enhancing the efficiency and reliability of microfluidic filtration processes.

Implementation Method 1

a filter (3), a ventilation channel (4), an inlet channel (1) and an outlet channel (6), the filter (3) being inserted into the inlet channel (1)

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

The liquid flow is driven by capillary forces

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2688670B1Fluidic system for bubbble-free filling of a microfluidic filter chamber
Publication Date: 2019.08.07 ROBERT BOSCH GMBH
  • EP2688670B1 patent drawingFigure 1a~1b
  • EP2688670B1 patent drawingFigure 2~3
  • EP2688670B1 patent drawingFigure 4

AI summary

The present invention relates to a microfluidic filter chamber having a controllable deaeration channel and use thereof. The invention also relates to a fluidic system for bubble-free filling of a microfluidic filter chamber and for filtering liquids, a method for bubble-free filling of a microfluidic filter chamber and a method for filtering liquids.