Fluid Sample Measuring Chamber Surface Structure for Symmetric Flow
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Solution Overview
Problem
Existing devices for accommodating fluid samples, particularly blood samples, face issues with trapped air and residual samples due to asymmetrical fluid propagation, which is exacerbated by changes in surface tension, leading to increased errors in analysis.
Innovation Solution
A device with a surface structure on the inner wall of the measuring chamber controls fluid propagation by restricting capillary forces, allowing for a uni-directional flow and adjusting pressure differences to ensure symmetrical filling and emptying, reducing the risk of trapped air and residual samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the surface tension inside the measuring chamber is changed (e.g., using silicone), then the fluid propagation is improved, but the risk of air entrapment and residual sample increases
Solution Approach 1:
The patent applies different surface properties to different regions of the measuring chamber. The inner wall surface has a specific surface structure (e.g., hydrophobic or hydrophilic regions, micro-patterns) that locally controls capillary forces to guide symmetric fluid propagation, while avoiding the use of silicone or other surface tension modifiers that cause air entrapment.
Solution Approach 2:
The patent introduces asymmetry in the surface structure of the measuring chamber walls to counteract the natural asymmetry in fluid propagation. By strategically placing surface features with different capillary properties at specific locations, the overall fluid flow becomes symmetric, preventing air pockets and residual samples.
2Measurement precision
If the measuring chamber dimensions are reduced for micro-analysis, then the analysis precision is improved, but the fluid propagation becomes asymmetrical increasing air entrapment risk
Solution Approach 1:
In micro-scale measuring chambers, the patent applies localized surface structures (e.g., hydrophobic barriers, hydrophilic pathways, micro-grooves) at specific regions to control capillary forces. This local modification ensures symmetric fluid propagation even in small dimensions, maintaining both measurement precision and reliability.
Solution Approach 2:
The patent addresses fluid propagation issues in micro-chambers by introducing surface features that operate in the vertical dimension (depth) rather than only in the horizontal plane. This dimensional approach allows control of capillary forces throughout the entire fluid path, ensuring symmetric propagation in miniaturized systems.
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 solution effectively minimizes the risk of trapped air and residual samples, decreasing errors related to poor wettability and inhomogeneous liquids, ensuring accurate and efficient analysis.
Implementation Method 1
a fluid propagation may be restricted at a wall of the measuring chamber compared to the center of the fluid front. In one embodiment, this is achieved by limiting a range of capillary forces to work in segments of limited size
Implementation Method 2
adjusting pressure differences to ensure symmetrical filling and emptying
Data Source
AI summary
A fluid (e.g., blood) sample may enter a measuring chamber of a multiple-use device via an inlet, flow through the measuring chamber, and leave the measuring chamber via an outlet. The device includes an inner wall surface defining an outer limit of the measuring chamber The inner wall surface includes a surface structure which is adapted to control a propagation of a flow front of the fluid sample in a direction (x) while the fluid sample enters into the measuring chamber via the inlet, while the fluid sample flows through the measuring chamber, and while the fluid sample leaves the measuring chamber via the outlet. The shape of the surface structure may be based on a flow speed of the flow front of the fluid sample, where the flow speed may be applied by a difference in pressure between the inlet and the outlet of the measuring chamber.