Continuous Flow Mixer With Offset Channels to Reduce Compositional Noise
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Solution Overview
Problem
Existing fluid chromatography systems face challenges in efficiently mixing fluids under laminar flow conditions, leading to compositional noise and reduced precision in sample quantification due to pump-induced discontinuities, which are not effectively addressed by current mixers that either increase volume or are prone to contamination and clogging.
Innovation Solution
A continuous flow mixer with a radially or axially symmetric channel structure that splits fluid flow into multiple branches, utilizing volume offsets and concentric stages to evenly distribute and recombine fluid flow, thereby reducing compositional ripple and enhancing mixing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large volume mixers are used to achieve effective mixing, then mixing performance is improved, but testing time increases and throughput diminishes
Solution Approach 1:
The mixer divides the fluid flow into multiple parallel channels (first and second inlet branches with multiple outlet branches each), allowing mixing to occur simultaneously across multiple pathways. This segmented approach achieves effective mixing without requiring a single large volume chamber, thereby maintaining throughput while improving mixing performance.
Solution Approach 2:
The invention transitions from traditional single-dimension mixing (sequential passage through a large chamber) to multi-dimensional mixing by creating a network of parallel channels with offset residence times. Fluids are mixed across spatial dimensions through the channel network rather than through temporal accumulation in a large volume, reducing delay volume while maintaining mixing effectiveness.
2Reliability
If packed-bead LC mixers are used for mixing, then mixing can be achieved, but they are inefficient relative to delay volume, difficult to manufacture, and prone to contamination and clogging
Solution Approach 1:
The invention extracts the mixing function from the complex packed-bead structure and implements it through a simplified channel network geometry. By removing the packed beads and replacing them with defined channels featuring offset residence times, the design achieves mixing capability while eliminating manufacturing complexity and contamination risks associated with packed structures.
Solution Approach 2:
The invention replaces the porous packed-bead structure with non-porous channel walls, eliminating the porosity-related issues of clogging and contamination while maintaining the flow distribution and mixing functions. The channel network provides defined flow paths without requiring porous materials.
3Power
If pumps deliver flow in discrete strokes, then positive displacement pumping is achieved, but compositional discontinuities cause noise and decrease precision in sample quantification
Solution Approach 1:
The mixer performs preliminary mixing action within each pump stroke by distributing fluid through multiple channels with offset residence times before the composition discontinuity occurs. This preliminary mixing smooths compositional variations within the stroke, reducing the amplitude of compositional ripples that would otherwise propagate through the system and degrade measurement precision.
Solution Approach 2:
The invention utilizes the periodic nature of pump strokes by designing channels with residence times synchronized to the pump frequency. The offset residence times create a periodic mixing pattern that counteracts the periodic compositional discontinuities introduced by the pump strokes, effectively canceling out the noise at the pump frequency and its harmonics.
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 mixer effectively cancels or reduces unwanted compositional oscillations, improving precision and throughput by minimizing pressure drop and delay volume, while being easy to manufacture and less susceptible to contamination.
Implementation Method 1
mixers require creative designs to promote controlled dispersion
Data Source
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AI summary
A continuous flow mixer for use in a chromatography system includes a first channel structure located between a mixer inlet and a mixer outlet. The first channel structure includes a first inlet branch, a second inlet branch, a plurality of outlet branches including at least a first outlet branch and a second outlet branch, a first plurality of branches splitting from the first inlet branch, each branch of the first plurality of branches connected to a different of the plurality of outlet branches, and a second plurality of branches splitting from the second inlet branch, each branch of the second plurality of branches connected to a different of the plurality of outlet branches. At least two branches of the first and second plurality of branches that are connected to the first outlet branch are offset in fluid residence time through the at least two branches.