Microfluidic Passive Valve With Flexible Layer Bending
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Solution Overview
Problem
Existing microfluidic devices face challenges in achieving high robustness and reliability, particularly in designs that can efficiently process small fluid volumes and require cost-effective manufacturing.
Innovation Solution
A microfluidic device design featuring a sequence of layers, including a first carrier layer, a flexible layer with a through-hole, and binding layers, where the flexible layer's bending induces passive valve functionality without external energy, allowing for efficient fluid directionality and compact, cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive valve is designed using multiple layers with a flexible layer for bending, then reliability is improved, but device complexity increases
Solution Approach 1:
The valve is divided into multiple functional layers: a first carrier layer with an aperture, a flexible layer with a through-hole, and a second carrier layer. Each layer performs a specific function, allowing the complex valve behavior to be achieved through simple, modular components that can be manufactured independently and assembled reliably.
Solution Approach 2:
A flexible layer with a through-hole is positioned between two carrier layers to form the passive valve. The flexibility of this layer allows it to bend and close the aperture in the first carrier layer when fluid pressure increases, providing reliable one-way valve functionality without requiring complex mechanical actuation mechanisms.
2Volume of moving object
If the flexible layer is positioned close to contacting layers, then device compactness is improved, but reliability deteriorates due to accidental sticking
Solution Approach 1:
Binding layers are introduced as intermediary elements between the flexible layer and the carrier layers. These binding layers serve as spacers that maintain an appropriate distance, preventing the flexible layer from accidentally sticking to the carrier layers while still allowing the valve to function compactly and reliably.
3Measurement precision
If external energy or control is used to actuate the valve, then valve control precision is improved, but ease of operation deteriorates due to additional actuation requirements
Solution Approach 1:
The passive valve operates autonomously by utilizing the kinetic energy and pressure differential of the flowing fluid itself to bend the flexible layer and close the aperture when reverse flow is detected. This self-actuating mechanism eliminates the need for external energy sources, control systems, or additional actuators, simplifying operation while maintaining precise flow direction control.
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 design achieves high reliability and cost-efficiency by utilizing a simple sequence of layers for passive valve functionality, reducing the need for external actuation and enabling compact, robust microfluidic cartridges for processing small fluid volumes.
Implementation Method 1
A flexible layer with at least one through-hole... pushing the flexible layer towards the first carrier layer closes the passage while pushing it towards the second carrier layer opens the passage
Data Source
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AI summary
A microfluidic device (100) comprising at least one passive valve (PV, 120, 130), the passive valve being constituted by a sequence of a first carrier layer (CL 1) with an aperture providing a passage (P 1) for fluid flow, a first binding layer (BLI) with a first opening, a flexible layer (FL) with a through-hole (TH), a second binding layer (BL2) with a second opening, and a second carrier layer (CL2). Moreover, the flexible layer (FL) can move within a valve chamber (VC) constituted by the openings. Depending on the pressure difference across the passive valve (PV), the flexible layer (FL) can bend towards the first carrier layer (CLI) and close the aperture, while it opens the passage (P1) when bending in the opposite direction. Two of such properly oriented passive valves together with an intermediate active valve (AV) can constitute a one-stroke pump. A method for manufacturing such a fluidic device is also disclosed.