Split-Flow Mixer Layout for Canceling LC Compositional Ripple

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Solution Overview

Problem

Existing chromatography systems face challenges in efficiently mixing fluids with compositional disturbances, leading to interference with sample detection and increased testing time, particularly in liquid chromatography systems, due to the inefficiency of large volume mixers and contamination issues with packed-bead mixers.

Innovation Solution

A fluid chromatography system with a mixer that splits the fluid flow into multiple paths with predetermined volume offsets and a balanced flow restrictor system to cancel unwanted compositional ripple, using a split-flow mixer design that includes a recombination system to ensure equal volume flow rates through each path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If large volume mixers are used to mix fluids effectively, then mixing effectiveness is improved, but testing time increases drastically and throughput diminishes

Engineering Contradiction:
Improvemixing effectivenessVSAvoidtesting time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The mixer divides the fluid flow into multiple parallel paths (first path and second path) that are offset by a predetermined volume. Each path processes a segment of the flow simultaneously, achieving effective mixing without requiring a large overall mixer volume, thus reducing testing time while maintaining mixing effectiveness.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If packed-bead LC mixers are used for mixing, then mixing is achieved, but they are inefficient relative to their delay volume, difficult to manufacture, and prone to contamination and clogging

Engineering Contradiction:
Improvemixing capabilityVSAvoidmanufacturing difficulty
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The invention removes the packed-bead component entirely from the mixing mechanism. Instead of using packed beads to achieve mixing, the system employs a streamlined split-flow design with offset paths that mixes fluids through flow dynamics alone, eliminating manufacturing complexity and contamination risks associated with packed beads.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical packed-bead mixing system with a fluid-dynamic mixing approach using offset flow paths. This substitution eliminates the need for complex mechanical structures while achieving effective mixing through the predetermined volume offset between parallel paths.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If pump cycles are used to deliver precise solvent compositions, then precise composition delivery is achieved, but compositional disturbances occur at regular intervals interfering with sample detection

Engineering Contradiction:
Improvecomposition precisionVSAvoidcompositional disturbances
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The mixer applies preliminary anti-action by offsetting the first and second paths by a predetermined volume before recombination. This volume offset creates a phase difference that causes compositional disturbances from pump cycles to cancel each other out during recombination, eliminating interference with sample detection while maintaining precise composition delivery.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP4341681B1Equal dispersion split-flow mixer
Publication Date: 2025.12.24 WATERS TECHNOLOGY CORP
  • EP4341681B1 patent drawingFigure 1
  • EP4341681B1 patent drawingFigure 2
  • EP4341681B1 patent drawingFigure 3

AI summary

Disclosed is a liquid chromatography system and mixer (100) for use therein that includes a first split 106 connected to an inlet (102), the first split branching the flow of fluid from the inlet into a first path (108) and a second path (110); a second split (112) connected to an outlet of the first path, the second split branching the first path into a third path (114) and a fourth path (116); and a third split (118) connected to an outlet of the second path, the third split branching the second path into a fifth path (120) and a sixth path (122). The first path and the second path are offset by a first predetermined volume, the third path and the fourth path are offset by a second predetermined volume, and the fifth path and the sixth path are also offset by the second predetermined volume.