Electrodialyser Separator Frame Thickness Optimization

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Solution Overview

Problem

Current membrane exchange devices face limitations in operating possibilities due to the need to maintain pressure balance between compartments, which can lead to membrane deformation, leakage, or rupture, especially when handling liquids with different viscosities or flow rates, resulting in uneven pressure drops and potential damage.

Innovation Solution

The device features compartments with varying joint plane thicknesses and distribution channel passage sections to adjust residence time and maintain equal pressure across all membranes, allowing for the efficient handling of liquids with different viscosities and flow rates by optimizing the thickness and structure of separator frames and membranes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of superimposed exchange cells is increased to enhance productivity, then the overall electrical resistance increases and energy consumption rises, but reducing membrane and separator frame thickness to limit electrode distance and reduce resistance creates structural weakness and compromises reliability

Engineering Contradiction:
Improvenumber of exchange cellsVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent changes the physical parameters of the separator frames by varying their thickness according to their position in the stack. Separator frames near the electrodes have greater thickness to provide structural support and reduce electrical resistance, while those in the middle have reduced thickness to minimize distance between membranes. This parameter optimization resolves the contradiction between maintaining low resistance (for energy efficiency) and providing structural integrity (for reliability).

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If membrane and separator frame thickness is reduced to minimize distance between electrodes and reduce electrical resistance, then energy consumption decreases, but the structural strength and reliability of the device deteriorate

Engineering Contradiction:
Improveelectrical resistanceVSAvoidmembrane support stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies local quality by making each separator frame's thickness adaptive to its specific location within the stack. Frames at critical positions (near electrodes) have increased thickness for structural support, while frames in less critical positions have reduced thickness. This localized optimization allows the device to maintain reliability where needed while minimizing overall resistance and energy consumption.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If uniform separator frame thickness is used across all compartments, then manufacturing simplicity is maintained, but the ability to handle liquids with different viscosities and flow rates is limited due to pressure balance constraints

Engineering Contradiction:
Improveseparator frame uniformityVSAvoidliquid handling capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent changes the geometric parameter of separator frame thickness to create compartments with different volumes and flow characteristics. By varying the thickness of separator frames, the device can accommodate liquids with different viscosities and flow rates in different compartments, optimizing pressure distribution and residence time for each specific liquid type while maintaining manufacturing feasibility through a standardized variable-thickness design.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If pressure balance between compartments is strictly maintained to prevent membrane deformation and rupture, then membrane integrity is preserved, but the device cannot efficiently handle liquids with different viscosities or flow rates

Engineering Contradiction:
Improvemembrane integrityVSAvoidoperating possibilities
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by creating compartments with different separator frame thicknesses to generate varied pressure distributions tailored to each compartment's specific liquid handling requirements. This allows the device to maintain membrane integrity in each local region while adapting to different liquid properties (viscosity, flow rate) in different compartments, thereby expanding operating possibilities without compromising overall reliability.

Inventive Principle:
Principle #3Local quality

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 configuration ensures a balanced pressure distribution across the entire stack, preventing membrane damage and enabling the efficient treatment of liquids with varying properties, such as different flow rates and viscosities, while minimizing energy consumption and maintaining membrane integrity.

Implementation Method 1

techniques using membranes, in particular ion exchange membranes

Methodology Applied
Scientific EffectIon Exchange: Ion Exchange

Implementation Method 2

In the electrodialysis technique, the device comprises two end electrodes and, between the two said electrodes, a certain number of identical electrodialysis cells, each cell being made up of two or more compartments, each compartment being delimited between two membranes selectively permeable to ions

Methodology Applied
Scientific EffectElectrodialysis:

Implementation Method 3

techniques of the dialysis, electrodialysis, reverse osmosis or ultrafiltration

Methodology Applied
Scientific EffectReverse Osmosis: Reverse Osmosis

Implementation Method 4

techniques of the dialysis, electrodialysis, reverse osmosis or ultrafiltration

Methodology Applied
Scientific EffectUltrafiltration:

Data Source

PatentEP2029263B1Membrane exchange device, an electrodialyser, with at least two compartments
Publication Date: 2010.09.15 EURODIA IND SA
  • EP2029263B1 patent drawingFigure 1
  • EP2029263B1 patent drawingFigure 2
  • EP2029263B1 patent drawingFigure 3

AI summary

In the membrane exchange device, an electrodialyser, with at least two compartments, each compartment defines a circuit for a given liquid and comprises a stack of membranes and dividing frames. Each frame is constituted of a joint member, the central part of which is a cavity that comprises a structure with holes (20). All the joint members (7, 8) and all the membranes (12) of a given circuit are pierced by the same flow orifices (13, 14, 23, 24) which, in the stack, form the piping for the entry and exit of the corresponding liquid. All the joint members of a given circuit are equipped with the same distribution channels connecting the flow orifices to the central cavity. The joint members of a given compartment are thicker than those of the other joint members or the other compartments and the flow space of the distribution channels and flow orifices of said given compartment is larger than that of the other distribution channels or other compartments. Said thickness and flow space are determined, for each compartment, so that the loss in charge at the membranes, due to the circulation of the liquid, is practically the same in each compartment.