Multi-Path Mixer for Compositional Noise Attenuation
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Solution Overview
Problem
Conventional microfluidic separation systems suffer from compositional noise in solvent gradients, which can lead to inaccurate and non-reproducible chromatography results due to the inefficiency of existing mixers in reducing these noise perturbations.
Innovation Solution
A multi-path mixer with a contoured surface is introduced, where the incoming solvent composition splits into multiple streams that recombine based on specific path geometries and dwell volumes, acting as a band stop filter to attenuate targeted frequencies of noise, thereby reducing compositional noise in the output solvent stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large-volume mixer is coupled to the output of the pump system to reduce compositional noise, then the compositional noise is reduced, but the delay volume increases which affects gradient accuracy and cycle time
Solution Approach 1:
The mixer is divided into multiple discrete fluidic paths (first path, second path, third path, fourth path) with different dwell volumes. Each path processes a portion of the solvent composition separately, allowing noise attenuation through path integration without requiring a large overall mixer volume. The segmentation of flow paths enables noise reduction while maintaining compact dimensions.
Solution Approach 2:
Each fluidic path is designed with specific local characteristics - different path lengths, different dwell volumes, and different geometries. The first path has a longer dwell volume than the second path, creating local variations in flow characteristics that collectively attenuate compositional noise when paths are integrated, without increasing the overall mixer volume.
2Reliability
If multiple pumps are used in high-pressure gradient systems to achieve binary gradients, then gradient mixing is improved, but the system complexity and cost increase
Solution Approach 1:
The single pump system is segmented into multiple fluidic paths within the mixer, where each path processes solvent composition differently. This path segmentation replaces the need for multiple pumps by creating virtual parallel processing channels within a single pump-mixer system, reducing complexity while maintaining gradient mixing capability.
Solution Approach 2:
The multi-path mixer acts as an intermediary device between the single pump and the chromatography column. It mediates the solvent composition by distributing flow through multiple paths with different dwell volumes, achieving gradient mixing functionality that would otherwise require multiple pumps, thereby simplifying the overall system.
3Object-affected harmful factors
If the mixer dwell volume is increased to reduce compositional noise, then noise attenuation is improved, but the gradient delivery accuracy and cycle time are negatively affected
Solution Approach 1:
The total dwell volume is segmented across multiple parallel fluidic paths rather than concentrated in a single large mixer chamber. Each path has a moderate dwell volume, and the parallel arrangement achieves noise attenuation through path integration without requiring a large overall dwell volume that would increase cycle time.
Solution Approach 2:
The mixer transitions from a single-dimension large-volume approach to a multi-dimensional parallel path architecture. By distributing flow through multiple paths with different dwell volumes in parallel, the system achieves noise attenuation in the frequency domain without increasing the overall volume dimension, thereby maintaining fast cycle times.
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 multi-path mixer effectively cancels specific frequency bands of noise, improving the accuracy and reproducibility of solvent gradients, enhancing the performance of liquid chromatography systems by reducing undesirable oscillations and delays.
Implementation Method 1
The mixer acts as a band stop filter to attenuate targeted frequencies of noise, thereby reducing compositional noise in the output solvent stream
Implementation Method 2
Neighboring valleys abut at a ridgeline, and solvent composition can overflow said ridgeline
Data Source
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AI summary
Mixers in microfluidic separation systems comprise multiple fluidic paths that extend from a distribution well to a mixing well. An incoming flow of solvent composition splits at the distribution well into as many streams as fluidic paths. The streams recombine at the mixing well to produce an output stream. One embodiment has fluidic paths with different dwell volumes that determine a percentage of the incoming flow flowing through each path. These dwell volumes can be targeted to attenuate a known noise characteristic in the incoming compositional flow. Another embodiment of mixer has a contoured surface disposed between the distribution and mixing wells. The paths extend from the distribution well to the mixing well through this contoured surface, each path passing through a different valley defined by opposing upwardly sloping banks. The valleys can have different dwell volumes that determine a percentage of the incoming compositional flow flowing through each valley.