Flat Sheet Membrane Structure With Integral Posts Against Delamination
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Solution Overview
Problem
Existing flat sheet filtration membranes, particularly those used in immersed configurations, face instability under high transmembrane pressures and frequent backwashes, leading to separation or delamination issues due to insufficient structural support and material thickness requirements.
Innovation Solution
Integration of posts extending from the separation layer, which are integral with the membrane material, providing structural support and enhancing resistance to compression and expansion during filtration and backwashing, while reducing material thickness and maintaining membrane integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flat sheet membranes are used in immersed applications, then the membrane can be installed and operated, but the membrane becomes unstable under large transmembrane pressures and frequent backwashes, leading to separation and delamination
Solution Approach 1:
The patent merges the separation layer and the supporting structure into a single integral membrane structure. The posts are formed from the same material as the separation layer through a continuous casting process, creating an inseparable unified structure that eliminates delamination issues while maintaining structural integrity under pressure and backwash conditions
Solution Approach 2:
The membrane comprises a composite structure with a separation layer and integrated posts formed from the same polymeric material. This composite design provides both the filtration functionality of the separation layer and the mechanical support of the posts, creating a structure that resists compression and expansion forces without delamination
2Productivity
If the membrane is made with a separation layer and supporting structure, then the membrane can perform filtration, but the supporting structure may separate or delaminate from the separation layer under high pressure
Solution Approach 1:
The supporting structure and separation layer are merged into a single integral structure where posts extend continuously from the separation layer. This eliminates the interface between separate components that could delaminate, while maintaining the filtration performance through the intact separation layer
Solution Approach 2:
The posts are formed simultaneously with the separation layer during the casting process, before the membrane is subjected to operational stresses. This preliminary formation ensures structural integrity is built into the membrane from the outset, preventing separation under subsequent high-pressure filtration and backwash conditions
Data Source
AI summary
A membrane, for example a flat sheet membrane, has posts extending from a separation layer. The posts extend through one or more supporting structures such as a substrate layer and/or a permeate carrier, between two separation layers, or both. A post may help to attach the separation layer to a supporting structure, attach two supporting structures together, strengthen a supporting structure and/or attach two separation layers together. In some examples, one or more supporting structures, which may be temporary or remain in the membrane, are made with openings for posts. A liquid containing the separating layer material is cast over the supporting structure or structures and some of the liquid flows at least part way through the openings before the liquid is solidified. A temporary supporting structure may be removed, for example dissolved. In other examples, two supporting structures are held apart in a casting knife while posts are formed.