Porous Polypropylene Support for Electrolytic Membrane Stress

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Solution Overview

Problem

Existing three-chamber electrolytic cells face issues such as exchange membrane failure, scaling, and increased voltage demands due to inefficient support structures that require precise alignment and can cause local polymer stress, leading to reduced ion transport and cell performance.

Innovation Solution

A porous nonwoven polypropylene fabric is used as a support member in the electrolytic cell, positioned adjacent to the exchange membranes to apply differential pressure from the intermediate chamber, eliminating the need for alignment and promoting efficient ion flux without interfering with fluid flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plastic netting, grids, or meshes are used as support structures, then the exchange membrane is supported and separated from electrodes, but the membrane makes small radius bends conforming to grid or mesh features, leading to local polymer stress and premature membrane failure

Engineering Contradiction:
Improvemembrane lifespanVSAvoidmembrane stress resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses a porous support structure with pores sized to match the cross-sectional dimensions of ion streams. This porous configuration allows the membrane to remain flat and unsupported in the regions between pores, eliminating small radius bends and local polymer stress concentrations that lead to premature failure. The porous structure provides necessary support while maintaining membrane integrity.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The support structure provides localized support only at specific pore locations rather than continuous support across the entire membrane surface. This local quality approach allows the membrane to be supported where ion transport occurs while remaining free and stress-free in intervening regions, preventing the development of harmful stresses.

Inventive Principle:
Principle #3Local quality

2Reliability

If support structures with perforations are used, then the exchange membrane is supported, but precise alignment of perforations in the support structure with perforations in the electrodes is required, and misalignment reduces ion transport and increases voltage demand

Engineering Contradiction:
Improvecell performance stabilityVSAvoidalignment precision requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameters of the support structure, specifically designing pores with dimensions (e.g., 0.5-5 mm) that are substantially the same as the cross-sectional dimensions of ion streams. This parameter matching allows the support structure to function effectively without requiring precise alignment with electrode perforations, as the porous configuration naturally accommodates ion transport pathways.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If support structures are used that allow exchange membranes to separate from electrodes, then the membrane is protected from direct contact, but efficient conversion of chloride to chlorine is reduced

Engineering Contradiction:
Improvemembrane protectionVSAvoidchloride to chlorine conversion efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The porous support structure provides a balanced solution by maintaining the membrane in close proximity to the electrode through localized support at pore locations, while allowing sufficient contact area for efficient chloride to chlorine conversion. The porous configuration ensures the membrane does not detach completely but also does not create harmful stress points.

Inventive Principle:
Principle #31Porous materials

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 solution provides stable membrane support, maintains chlorine output, reduces voltage requirements, and prevents membrane deformation, resulting in improved cell performance and uniform ion delivery.

Implementation Method 1

a porous material provides a means of support to an exchange membrane within an electrolytic cell by applying a differential pressure from an intermediate chamber of a cell to the exchange membrane and an electrode

Methodology Applied
Scientific EffectDifferential pressure: Pressure Gradient

Implementation Method 2

promoting efficient ion flux without interfering with fluid flow

Methodology Applied
Scientific EffectIon flux: Ion Repulsion/Attraction

Implementation Method 3

the production of acidic electrolyzed water and alkaline electrolyzed water by the electrolysis of water in which chlorine electrolyte has been added

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Data Source

PatentEP3135797B1Support of ion exchange membranes
Publication Date: 2019.08.21 ECOLAB USA INC
  • EP3135797B1 patent drawingFigure 1
  • EP3135797B1 patent drawingFigure 2
  • EP3135797B1 patent drawingFigure 3

AI summary

A support member for an improved three-chambered electrolytic cell is disclosed. A porous synthetic support system for exchange membranes in electrolytic cells is used for exchange membrane protection in electrolytic cells for the in situ generation of electrolysis solutions, such as bleach or hypochlorous acid.