Electrodialysis Manifold Layout to Resist Current Bypass

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Solution Overview

Problem

Existing electrochemical separation devices, particularly cross-flow electrodialysis devices, suffer from inefficiencies due to current bypass through inlet and outlet manifolds, leading to reduced current efficiency, increased energy consumption, and higher membrane requirements, which affect manufacturing costs and space requirements.

Innovation Solution

The implementation of modular electrochemical separation systems with flow directors and manifolds configured to promote current efficiency by creating tortuous bypass paths with higher resistance than direct paths through the cell stack, and using multi-pass flow configurations with blocking membranes or spacers to direct fluid streams effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional manifold designs are used in electrodialysis devices, then fluid distribution is simple, but current bypass through manifolds increases leading to reduced current efficiency

Engineering Contradiction:
Improvecurrent efficiencyVSAvoidmanifold design complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The device is divided into multiple modular units, each with its own cell stack and frame assembly. This segmentation allows current to be distributed through multiple independent pathways rather than relying on a single manifold system, reducing current bypass through the manifolds and improving current efficiency while maintaining manageable complexity through standardization of modular components

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Electrically insulating materials and structures are introduced as intermediaries between conductive components. The frames and spacers use electrically insulating materials to prevent unwanted current pathways through the manifold system, directing current flow through the ion-exchange membranes where it performs the separation function, thereby improving current efficiency without significantly complicating the overall device structure

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If higher membrane area is used to compensate for current bypass, then separation capacity is maintained, but manufacturing costs and space requirements increase

Engineering Contradiction:
Improveseparation capacityVSAvoidmanufacturing cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The design converts the potential harm of current bypass into a benefit by using electrically insulating frames and spacers that strategically direct current flow. This approach reduces wasteful current pathways while maintaining or enhancing separation capacity, thereby reducing the total membrane area needed and lowering manufacturing costs without sacrificing productivity

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention changes the electrical conductivity parameters of the device structure by introducing electrically insulating materials in strategic locations. This parameter change redirects current flow from low-resistance manifold pathways through the high-value ion-exchange membranes, improving current efficiency and reducing the membrane area required for a given separation capacity, thus lowering manufacturing costs

Inventive Principle:
Principle #35Parameter changes

3Productivity

If higher membrane area is used to compensate for current bypass, then separation capacity is maintained, but device footprint increases

Engineering Contradiction:
Improveseparation capacityVSAvoiddevice footprint
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The design converts the potential harm of current bypass into a benefit by using electrically insulating frames and spacers that strategically direct current flow. This approach reduces wasteful current pathways while maintaining or enhancing separation capacity, thereby reducing the total membrane area needed and lowering manufacturing costs without sacrificing productivity

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The frame and spacer structures serve multiple functions simultaneously: they provide mechanical support for the membranes, maintain compartment spacing, prevent short-circuiting of fluid streams, and block current bypass pathways. This multi-functionality reduces the need for separate components and allows more efficient use of membrane area, decreasing device footprint while maintaining separation capacity

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

This approach enhances current efficiency to at least 85%, reduces membrane requirements, and lowers manufacturing costs, making the process more cost-competitive with reverse osmosis for desalination applications.

Implementation Method 1

configured to promote current efficiency by creating tortuous bypass paths with higher resistance than direct paths through the cell stack

Methodology Applied
Scientific EffectFluid flow resistance: Pressure Drop

Implementation Method 2

a fluid flow director disposed within the inlet manifold and having a surface configured to alter a flow path of fluid introduced into the inlet manifold and direct the fluid into one of the depleting compartments or the concentrating compartments

Methodology Applied
Scientific EffectFluid flow direction: Pressure Gradient

Implementation Method 3

An applied electric field imposed via electrodes causes dissolved ions, attracted to their respective counter-electrodes, to migrate through the anion and cation exchange membranes

Methodology Applied
Scientific EffectIon migration: Electrophoresis

Implementation Method 4

dissolved ions, attracted to their respective counter-electrodes, to migrate through the anion and cation exchange membranes

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 5

Devices for purifying fluids using electrical fields may be used to treat water and other liquids containing dissolved ionic species

Methodology Applied
Scientific EffectElectrodialysis:

Data Source

PatentEP3641848B1Design of fluid manifolds in electrodialysis devices
Publication Date: 2025.12.03 EVOQUA WATER TECHNOLOGIES LLC
  • EP3641848B1 patent drawingFigure 1A~1B
  • EP3641848B1 patent drawingFigure 1C~1E
  • EP3641848B1 patent drawingFigure 2A~2B

AI summary

An electrochemical separation device includes a first electrode, a second electrode, a cell stack including alternating depleting compartments and concentrating compartments disposed between the first electrode and the second electrode, an inlet manifold configured to introduce a fluid to one of the depleting compartments or the concentrating compartments an outlet manifold, and one or more of a fluid flow director disposed within the inlet manifold and having a surface configured to alter a flow path of the fluid introduced into the inlet manifold and direct the fluid into the one of the depleting compartments or the concentrating compartments, and a second fluid flow director disposed within the outlet manifold and having a surface configured to alter a flow path of the fluid introduced into the outlet manifold via one of the depleting compartments or the concentrating compartments.