Microfluidic Stop With Flexible Membrane Flow Actuation

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Solution Overview

Problem

Existing fluidic systems lack robust control over fluid flow, particularly in microfluidic systems, where reliable and efficient transport of biological media like blood, saliva, and urine is required without affecting internal pressure.

Innovation Solution

A microfluidic system with a flexible element that deforms under external pressure, reducing the distance between its inner surface and opposing elements to enable fluid flow across a fluidic stop, allowing capillary suction or pressure-driven transport without requiring pressure changes within the medium.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fluidic stop is used to interrupt flow, then flow control reliability is improved, but device complexity increases due to additional components

Engineering Contradiction:
Improveflow control reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the fluidic stop function with the channel wall structure itself. The flexible element is integrated into the channel geometry, eliminating the need for separate stop components. This merging approach maintains reliable flow interruption while reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a flexible element (thin film) that can deform to control fluid flow. This flexible membrane serves as both the channel boundary and the flow control mechanism, allowing reliable flow interruption through deformation rather than requiring complex mechanical stops.

Inventive Principle:
Principle #30Flexible shells and thin films

2Manufacturing precision

If external pressure is applied to deform the flexible element, then flow control precision is improved, but the risk of affecting internal medium pressure increases

Engineering Contradiction:
Improveflow control precisionVSAvoidinternal pressure disturbance
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent segments the pressure application zone from the fluid medium zone. The flexible element acts as a barrier that transmits only the necessary deformation signal while isolating the external actuation pressure from the internal fluid medium, thus maintaining precise flow control without disturbing medium pressure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexible element serves as an intermediary between the external actuation mechanism and the internal fluid medium. It converts external pressure into controlled deformation that regulates flow without allowing direct pressure transmission to the medium, thereby maintaining flow precision while avoiding harmful pressure effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If the distance between flexible element inner surface and opposing element is reduced, then flow enablement speed is improved, but structural stability deteriorates

Engineering Contradiction:
Improveflow enablement speedVSAvoidstructural stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent implements a dynamic gap between the flexible element and the opposing structure. The gap size changes based on operational requirements: larger during idle states for stability, and reduced during flow enablement for speed. This dynamic adjustment allows the system to achieve fast flow activation while maintaining structural stability during non-operational phases.

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

Enables reliable and robust control of fluid flow by interrupting flow at a fluidic stop until deformation occurs, ensuring efficient transport and filtering of biological media without altering internal pressure, suitable for applications like biosensing and sample processing.

Implementation Method 1

a flexible element having an inner surface arranged such that a determined mechanical pressure applied on an outer surface of the flexible element leads to a local deformation of the inner surface reducing a distance (Δ) between said inner surface and the opposing element

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

allowing capillary suction or pressure-driven transport without requiring pressure changes within the medium

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2931427B1Fluidic system with fluidic stop
Publication Date: 2022.02.09 SIEMENS HEALTHINEERS NEDERLAND BV
  • EP2931427B1 patent drawingFigure 1a~1c
  • EP2931427B1 patent drawingFigure 2~4
  • EP2931427B1 patent drawingFigure 5~7

AI summary

An embodiment of the invention relates to a fluidic system (200) in which a first channel (210) and a second channel (230) are separated by a fluidic stop (220), for example a region with a hydrophobic coating and/or a structure (220) with non-capillary internal dimensions. Moreover, it comprises a flexible element (240) that is deformable to enable a flow of a medium across the fluidic stop.