Phase Inversion Membrane Surface Roughness via Strand Compression

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Solution Overview

Problem

Existing methods for producing phase inversion membranes lack the ability to easily create a rough membrane surface, which limits the membrane's flow rate and separation performance.

Innovation Solution

A method involving a device that guides a polymer strand along a process route with varying transport speeds using multiple conveying units, allowing for compression and stretching, and passing through precipitation baths to achieve a rough membrane surface, increasing the membrane's surface area and flow rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the polymer strand is guided along the process path at different transport speeds for compression and stretching, then the membrane surface roughness is improved, but the risk of polymer strand damage increases

Engineering Contradiction:
Improvemembrane surface roughnessVSAvoidpolymer strand integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The conveying units are equipped with variable speed drives that allow dynamic adjustment of transport speeds during membrane production. The control unit continuously monitors and adjusts the speed differences between conveying units to achieve optimal compression and stretching effects while preventing polymer strand damage through real-time feedback control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the transport speed parameter of each conveying unit independently to control the degree of compression and stretching. By precisely controlling the speed differential between adjacent conveying units, the system achieves the desired surface roughness while maintaining polymer strand integrity through parameter optimization.

Inventive Principle:
Principle #35Parameter changes

2Area of moving object

If multiple conveying units with different transport speeds are used, then the membrane surface area is increased, but the device complexity increases

Engineering Contradiction:
Improvemembrane surface areaVSAvoidconveying unit configuration
Core Design Contradiction:
Area of moving objectVSDevice complexity

Solution Approach 1:

Each conveying unit is designed with multi-functionality, serving both as a transport mechanism and as a compression/stretching element. The conveying units share common structural components and control systems, allowing them to perform multiple functions simultaneously, thereby increasing membrane surface area while limiting the increase in overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If the transport speed difference between conveying units is increased, then the compression and stretching effect is enhanced, but the polymer strand may be damaged

Engineering Contradiction:
Improvesurface roughness depthVSAvoidpolymer strand strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The control unit incorporates feedback mechanisms that monitor the transport speeds of all conveying units and adjust them in real-time. Based on feedback signals about polymer strand tension and deformation, the system automatically optimizes the speed differential to achieve the required surface roughness depth while preventing excessive stress that could damage the polymer strand.

Inventive Principle:
Principle #23Feedback

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 method effectively produces a membrane with a rough surface, enhancing its flow rate and separation performance by increasing the actual membrane surface area and turbulence, while preventing damage to the polymer strand.

Implementation Method 1

The polymer strand exiting the spinneret is guided through four precipitation baths to remove a solvent and thus to coagulation, whereby the polymer strand forms into the membrane along the process path and assumes a solid state

Methodology Applied
Scientific EffectPhase inversion: Phase Change

Implementation Method 2

guided through four precipitation baths to remove a solvent and thus to coagulation

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 3

the polymer strand is guided along the process path at different transport speeds for compression and stretching, wherein the polymer strand is selectively compressed and stretched by the device to provide a rough inner membrane surface

Methodology Applied
Scientific EffectCompression and stretching: Deformation

Data Source

PatentEP2688663B1Method for producing a membrane
Publication Date: 2022.05.18 OECHSLE DIETMAR
  • EP2688663B1 patent drawingFigure 1
  • EP2688663B1 patent drawingFigure 2

AI summary

The invention relates to a membrane producing device, in particular a phase inversion membrane producing device that has at least one transport section (10) which is provided for guiding a polymer strand (12) in order to form a membrane, in particular a phase inversion membrane. The membrane producing device has at least one device (14) that is provided for compressing and/or expanding the polymer strand (12) in a controlled manner in at least one sub-region (16, 18, 20, 22, 24, 26) of the transport section (10).