Chromatography Mixer Arrangement Using Split-Flow Delay and Porous Dispersion
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Solution Overview
Problem
Chromatography systems face issues with noise generation due to pump strokes, leading to compositional discontinuities and reduced precision in sample quantification, particularly in liquid chromatography systems where turbulence is lacking for effective mixing.
Innovation Solution
A mixer arrangement comprising frequency targeting mixers and residual noise targeting mixers, including split-flow channels with volume offset regions and a mixing disk with a random porous structure, to reduce or eliminate fluidic compositional oscillations and dampen aperiodic baseline noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If large volume mixers are used to mix fluids effectively, then mixing performance is improved, but testing time increases and throughput diminishes
Solution Approach 1:
The mixer is divided into multiple discrete mixing elements (mixing segments) arranged in series. Each segment contributes to the overall mixing function, allowing effective mixing to be achieved with a much shorter total mixer length compared to traditional large volume mixers, thereby reducing testing time while maintaining mixing performance.
Solution Approach 2:
The mixer incorporates porous support structures and packed beads that provide high surface area and turbulent flow paths within a compact volume. This allows efficient mixing to occur in a short distance, eliminating the need for long mixing zones while maintaining effective compositional homogenization.
2Volume of moving object
If packed-bead LC mixers are used, then compact size is achieved, but they are inefficient relative to delay volume, difficult to manufacture, and prone to contamination and clogging
Solution Approach 1:
The mixer uses sintered metal or ceramic porous structures instead of packed beads. These porous materials provide the necessary flow resistance and mixing turbulence while having smooth internal surfaces that resist contamination and clogging. The porous structure is also more durable and easier to manufacture as a single integrated component compared to packed bead assemblies.
Solution Approach 2:
The mixer employs composite structures combining different materials (e.g., sintered metal with coating, or ceramic with protective layer) to achieve both compact size and resistance to contamination. The composite nature allows optimization of both mechanical strength and surface properties for contamination resistance.
3Measurement precision
If piston or syringe style positive displacement pumps are used, then precise flow delivery is achieved, but compositional discontinuities between strokes generate noise
Solution Approach 1:
The mixer is designed to perform preliminary mixing action immediately after each pump stroke delivers solvent. The mixing elements are positioned to receive and homogenize the discrete stroke volumes before they enter the detection cell, eliminating compositional discontinuities and associated noise at the source rather than attempting to filter or correct them downstream.
Solution Approach 2:
The mixer creates continuous turbulent mixing and compositional homogenization that bridges the discrete gaps between pump strokes. This continuous mixing action ensures that even though the pump delivers fluid in discrete volumes, the composition remains homogeneous and stable throughout the flow, eliminating the periodic compositional variations that cause noise.
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 arrangement effectively reduces noise, enhancing sample detection precision and increasing the number of detectable peaks in complex mixtures by minimizing signal-to-noise ratio loss and improving compound identification.
Implementation Method 1
the second flow channel including a volume offset region configured to delay fluid propagation through the second flow channel, wherein the volume offset region is configured to reduce or eliminate fluidic compositional oscillations in a compositional solvent stream that depart from a desired composition at a first target frequency
Implementation Method 2
the residual noise targeting mixer includes a mixing disk having an inlet face and an outlet face located between the plurality of flow channels, wherein the mixing disk includes a dispersive medium having a random porous structure
Implementation Method 3
the residual noise targeting mixer includes a dispersion structure having a plurality of flow channels creating flow direction anisotropy
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A mixer arrangement for use in a chromatography system includes a first frequency targeting mixer (30) including a first flow channel (32) coupled between an inlet (31) and an outlet 39 and a second flow channel (32) coupled between the inlet (32) and the outlet (31), the second flow channel (32) including a volume offset region (35) configured to delay fluid propagation through the second flow channel, wherein the volume offset region (35) is configured to reduce or eliminate fluidic compositional oscillations in a compositional solvent stream that depart from a desired composition at a first target frequency, and a residual noise targeting mixer (40) fluidically connected in series to the frequency targeting mixer (30), the residual noise targeting mixer (40) configured to dampen aperiodic baseline noise in the compositional solvent stream.