Fluid Mixer with Density-Based Splitter for HPLC Noise Reduction

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Solution Overview

Problem

Conventional fluid mixers in high-pressure gradient HPLC systems suffer from compositional noise due to differing dwell volumes in fluidic paths, leading to inconsistent channel clearance and increased downtime during solvent changes, and existing solutions either fail to adequately reduce noise or introduce undesirable delay volumes.

Innovation Solution

A fluid mixer design featuring a splitter plate that splits fluid streams by density, with channels of dissimilar volumes but identical pressure drops across each channel, ensuring identical volumetric flow rates and promoting homogeneous mixing, and a series arrangement of mixers to enhance mixing and turbulence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional fluid mixers are used to reduce compositional noise, then compositional noise is reduced, but delay volume increases and cycle time increases

Engineering Contradiction:
Improvecompositional noiseVSAvoidcycle time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The fluid stream is divided into multiple parallel channels with different dwell volumes, allowing noise reduction through recombination while maintaining low overall delay volume. The segmentation of flow paths enables selective damping of compositional noise without requiring a single large-volume mixer.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple channels with different dwell volumes are nested within a compact mixer structure, allowing the system to achieve noise reduction equivalent to larger mixers while maintaining a compact form factor and minimal delay volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Stability of the object's composition

If channels of dissimilar volumes are used, then mixing homogeneity is improved, but channel clearance consistency deteriorates

Engineering Contradiction:
Improvemixing homogeneityVSAvoidchannel clearance consistency
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

Each channel is designed with specific local characteristics (different dwell volumes) optimized for mixing homogeneity, while the overall system maintains consistent performance through balanced design. The local variations in channel volume are deliberately engineered to improve mixing while the global design ensures acceptable clearance consistency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The dwell volume parameter is varied across different channels to optimize mixing homogeneity. By changing this physical parameter selectively in different channels, the system achieves superior mixing while managing the trade-off with clearance consistency through overall system balancing.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple pumps are used in high-pressure gradient systems, then gradient precision is improved, but system complexity increases

Engineering Contradiction:
Improvegradient precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple fluid streams from different pumps are merged in parallel channels within a single mixer, allowing gradient precision to be maintained through combined flow control while reducing system complexity by consolidating multiple pump outputs into one mixing chamber rather than requiring sequential processing.

Inventive Principle:
Principle #5Merging (Combining)

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 reduces compositional noise and ensures consistent channel clearance, improving the homogeneity of mixed fluids and reducing cycle time by maintaining minimal dwell volume.

Implementation Method 1

a splitter plate configured to split the stream of fluid into a first stream and a second stream, the first stream having a lower density than the second stream

Methodology Applied
Scientific EffectDensity stratification: Density Gradient

Implementation Method 2

a mixing chamber configured to receive the first stream and the second stream and promote homogeneous mixing of the first stream and the second stream

Methodology Applied
Scientific EffectTurbulent mixing: Turbulence

Data Source

PatentEP3678764B1Fluid mixer
Publication Date: 2022.07.27 WATERS TECHNOLOGY CORP
  • EP3678764B1 patent drawingFigure 1
  • EP3678764B1 patent drawingFigure 2
  • EP3678764B1 patent drawingFigure 3~4

AI summary

A fluid mixer includes a flow splitter and a mixing chamber. The flow splitter includes an inlet for receiving a flow of fluid and is configured to split the flow of fluid into first and second fluid streams. The second fluid stream has a higher density than the first fluid stream. The mixing chamber includes a first inlet, a second inlet and a mixing well. The second inlet is positioned below the first inlet. The second inlet of the mixing chamber is configured to receive the first fluid stream and the first inlet of the mixing chamber is configured to receive the second fluid stream to promote mixing of the first and second streams in the mixing well.