Non-nesting Spacing Features for Spiral-Wound Membrane Elements
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Solution Overview
Problem
Spiral-wound membrane filtration elements face flow restriction and membrane fouling due to the presence of conventional porous feed spacers, which cause pressure drops and facilitate biological growth, scale formation, and particle capture.
Innovation Solution
The introduction of embossed or deposited spacing features on the membrane surface that discourage nesting when spirally wound, providing non-uniform spacing or angle variations to maintain open flow channels and prevent occlusion, thereby reducing fouling and pressure drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional porous feed spacers are used to maintain spacing in spiral-wound elements, then structural support and flow channel maintenance are achieved, but flow restriction and pressure drop increase significantly
Solution Approach 1:
The patent removes the conventional porous feed spacer component entirely and replaces it with spacing features that are directly formed on the membrane surface through embossing or deposition. This extraction of the separate spacer component eliminates the flow restriction and pressure drop issues while maintaining the necessary spacing function.
Solution Approach 2:
The spacing function previously performed by a separate feed spacer component is merged with the membrane structure itself. The spacing features are integrated directly onto the membrane surface, combining the spacing function with the membrane's structural role, thereby eliminating the need for a distinct spacer component.
2Ease of operation
If conventional porous feed spacers are used to maintain spacing, then open flow channels are maintained, but membrane fouling increases due to biological growth, scale formation, and particle capture
Solution Approach 1:
By removing the separate feed spacer component and replacing it with integrated spacing features on the membrane surface, the patent eliminates the spacer material that serves as a substrate for biological growth, scale formation, and particle accumulation, thereby reducing fouling while maintaining open flow channels.
Solution Approach 2:
The spacing features are designed with specific local geometries (protrusions, ridges, or embossed patterns) that create open flow channels while minimizing surface area available for fouling. The local structure is optimized to promote fluid flow and reduce stagnation zones where fouling typically occurs.
3Shape
If feed spacers are used to prevent nesting of membrane layers, then spacing is maintained, but device complexity increases due to additional components
Solution Approach 1:
The patent combines the spacing function with the membrane structure by directly forming spacing features on the membrane surface through embossing or deposition. This integration eliminates the need for a separate feed spacer component, reducing device complexity while maintaining effective spacing to prevent nesting of membrane layers during spiral winding.
4Ease of manufacture
If uniform spacing features are used on the membrane surface, then manufacturing is simplified, but nesting of spacers occurs when spirally wound
Solution Approach 1:
The patent employs asymmetric or varied spacing feature patterns where the spacing between features is not uniform but varies in a controlled manner. This asymmetry prevents the periodic nesting that occurs with uniform patterns during spiral winding, while the features are still formed through straightforward embossing or deposition processes that maintain ease of manufacture.
Data Source
AI summary
Embodiments of the present invention provide for the deposition of spacing elements for spiral wound elements that prevent nesting of adjacent spacer layers and occlusion of feed space during element rolling.