Flow Cell With Offset Sheath Paths for Laminar Specimen Focusing
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Solution Overview
Problem
Existing flow cells face challenges in maintaining a laminar flow state of specimen fluid at the central portion within the sheath fluid while minimizing mixing, leading to inefficiencies in fluid consumption and imaging capabilities.
Innovation Solution
A flow cell design featuring intersecting sheath fluid paths with offset introducing openings and a tapered merging portion to ensure the specimen fluid flows in a laminar state at the central depth of the sheath fluid, suppressing mixing and optimizing fluid flow for imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the flow path downstream of the flow cell is made narrow to squeeze the entire fluid, then the specimen fluid can be imaged by a camera, but the specimen fluid and sheath fluid mix together at the merging point and some specimen fluid falls outside the depth of field
Solution Approach 1:
The patent introduces a depth dimension consideration by creating a tapered portion that gradually narrows the flow path depth downstream. This dimensional transition allows the specimen fluid to be compressed into the focal plane of the camera while maintaining laminar flow structure, solving the contradiction between imaging precision and fluid layering stability.
Solution Approach 2:
The patent changes the flow path parameters (width and depth) along the downstream direction by incorporating a tapered portion. This gradual parameter change allows the fluid to transition from a wider, deeper configuration at the merging point to a narrower, shallower configuration at the imaging point, maintaining stability while achieving precise imaging.
2Device complexity
If the volume of the flow cell is large to accommodate fluid flow, then the flow cell structure can be simple, but the amount of sheath fluid consumed is large
Solution Approach 1:
The patent segments the flow cell into distinct functional portions: a merging portion for fluid introduction, a tapered portion for flow compression, and an imaging portion for observation. This segmentation allows each section to be optimized for its specific function, reducing overall fluid volume requirements while maintaining structural simplicity.
Solution Approach 2:
By utilizing the depth dimension through the tapered portion design, the patent achieves fluid compression without increasing the planar footprint of the flow cell. This dimensional approach reduces the total fluid volume needed while keeping the structural design straightforward.
3Loss of substance
If a flow contracting portion with small flow path width and depth is provided to collect specimen fluid at the center, then sheath fluid consumption is reduced, but this structure is unsuitable for imaging specimen fluid by a camera
Solution Approach 1:
The patent creates a dynamic transition in the flow path configuration through the tapered portion, which gradually changes from a larger cross-section at the merging point to a smaller cross-section at the imaging point. This dynamic design allows the system to accommodate both fluid collection efficiency and imaging requirements at different locations along the flow path.
Solution Approach 2:
The patent employs parameter changes along the flow path, specifically the gradual reduction of flow path width and depth in the tapered portion. This controlled parameter transition enables the system to achieve both low sheath fluid consumption and adequate imaging conditions by optimizing the parameters at different locations rather than using a uniform configuration.
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 effectively maintains a laminar flow state of the specimen fluid at the central portion within the sheath fluid, reducing mixing and enhancing imaging capabilities while minimizing sheath fluid consumption and manufacturing costs.
Implementation Method 1
causes the specimen fluid to flow in a laminar flow state at the central portion in the depth direction of the sheath fluid
Implementation Method 2
the specimen fluid and the sheath fluid mix together at a merging point, and, thereafter, even though the fluids are converged
Data Source
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AI summary
A flow cell has: a flow path in which a specimen fluid and a sheath fluid flow; a specimen flow path that introduces the specimen fluid into the flow path; a first sheath flow path and a second sheath flow path that introduce the sheath fluid into the flow path; and a merging portion at which the specimen flow path, the first sheath flow path and the second sheath flow path merge together. The specimen flow path is provided on a central flow line of the flow path. At the merging portion, the first sheath flow path and the second sheath flow path face directions intersecting the central flow line of the flow path, and are disposed at positions that are offset in a depth direction of the flow path.