Membrane Stack Compression Molding for Electrodialysis

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Solution Overview

Problem

Existing methods for preparing membrane stacks for electrodialysis are time-consuming and costly, requiring manual or mechanical gluing or heat-sealing of multiple membranes, which leads to inefficiencies and increased costs.

Innovation Solution

A method involving the alignment and compression of membranes with edges forming a seal, followed by molding and solidification of a liquid compound to create a membrane stack, which can be done quickly and cost-effectively, enhancing mechanical stability and leak-free operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If membranes are glued together or heat-sealed using conventional methods, then the membrane stack is sealed and functional, but the process is time-consuming and costly

Engineering Contradiction:
Improvesealing qualityVSAvoidassembly speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces manual or mechanical gluing/heat-sealing operations with a compression molding process. Membranes are stacked and compressed under heat and pressure, causing them to fuse together through thermal compression rather than requiring separate sealing operations. This substitution of the sealing mechanism dramatically reduces assembly time and cost while maintaining reliable seals.

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

Solution Approach 2:

The patent combines multiple process steps into a single compression molding operation. Instead of separately assembling membranes, applying adhesive, and then sealing, all these functions are integrated into one compression step where membranes are stacked and simultaneously fused and sealed through applied heat and pressure.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple process steps are used for gluing or heat-sealing membranes, then the membrane stack achieves proper sealing, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvesealing qualityVSAvoidprocess steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple separate process steps (membrane assembly, adhesive application, sealing) into a single compression molding operation. The membranes are stacked in sequence and then compressed together in one step, eliminating the need for intermediate sealing operations and reducing overall process complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the sealing function from the assembly process by using the compression molding pressure and heat to create the seal during the stacking operation itself, rather than requiring separate sealing steps. The compression force and thermal energy are extracted as the primary sealing mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If conventional gluing or heat-sealing methods are used, then membranes are connected, but extensive materials and labor are required

Engineering Contradiction:
Improvemechanical stabilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent replaces complex multi-step mechanical sealing systems with a simple compression molding process. By applying heat and pressure during stacking, the membranes fuse together through thermal compression, eliminating the need for adhesives, separate sealing tools, and multiple operational steps.

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

Solution Approach 2:

The patent utilizes changes in temperature and pressure parameters during the compression molding process to achieve membrane fusion. By controlling the thermal and mechanical parameters during stacking, the membranes transition from separate components to a fused, mechanically stable structure in one operation.

Inventive Principle:
Principle #35Parameter changes

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 allows for the rapid and cost-efficient assembly of membrane stacks with improved mechanical stability and leak-free performance, reducing the need for extensive materials and labor, making it suitable for mass production and use in developing countries.

Implementation Method 1

compressing the membrane stack after step (a) to sealingly connect the edges to prevent a liquid compound from penetrating the at least one flow channel

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

molding the according to step (a) formed membrane stack by the liquid compound to seal the at least two membranes

Methodology Applied
Scientific EffectMolding:

Implementation Method 3

solidifying the liquid compound as sealing of the membrane stack

Methodology Applied
Scientific EffectSolidification: Freezing

Data Source

PatentEP3599012B1Method for preparing a membrane stack, membrane stack and use of the membrane stack
Publication Date: 2022.05.04 GRABOWSKI ANDREJ
  • EP3599012B1 patent drawingFigure 1
  • EP3599012B1 patent drawingFigure 2
  • EP3599012B1 patent drawingFigure 3

AI summary

The invention relates to method for preparing a membrane stack (2) for electrodialysis having at least two membranes (1), a cation-exchange membrane and an anion-exchange membrane, preferably membranes (1) having a profiled surface, in which the at least two membranes (1) comprise at least one flow channel (8), an inlet (4) and an outlet (5), the method comprising the steps (a) aligning the at least two membranes (1) with each other so that edges (6) of the at least one flow channel (8), the inlet (4) and the outlet (5) through the at least two aligned membranes (1) are closed to form a membrane stack (2) of alternately stacked membranes (1), (b) molding, preferably overmolding, the according to step (a) formed membrane stack (2) by a liquid compound (16) to seal the at least two membranes (1), and (c) solidifying the liquid compound (16) as sealing of the membrane stack (2) as well as a membrane stack (2) according to the method for preparing a membrane stack (2) for electrodialysis and the use of the membrane stack (2).