Membrane Separation Device Narrowing Member Bulge Control
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Solution Overview
Problem
In membrane separation devices used for sewage and wastewater treatment, continuous aeration without filtration operation leads to bulging of separation membranes, causing increased force and risk of rupture, especially at the outermost membrane elements due to uncontrolled upward flow and gas evaporation.
Innovation Solution
A narrowing member is provided outside the outermost membrane element at a predetermined distance smaller than the fixed interval between membrane elements, restricting the bulge and reducing the angle between the membrane support body and separation membrane, thereby minimizing the risk of rupture by distributing the force more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous aeration is performed without filtration operation, then the membrane separation function is maintained and fouling is prevented, but the separation membrane bulges upward forming a big bulging portion that causes vibrations and increases rupture risk
Solution Approach 1:
A narrowing member is introduced as an intermediary component between the separation membrane and the outermost cover member. This narrowing member acts as a mediator that restricts the upward bulge of the separation membrane during continuous aeration, preventing the formation of large bulging portions while maintaining the membrane separation function and reducing rupture risk.
2Adaptability or versatility
If the separation membrane is allowed to bulge freely during continuous aeration, then the upward flow and gas evaporation are accommodated, but the angle between the membrane support body and separation membrane increases causing large force application and rupture risk
Solution Approach 1:
The narrowing member is strategically positioned at the outermost end of the membrane element assembly, creating a localized restriction point. This local quality change allows the separation membrane to bulge freely in most areas to accommodate upward flow and gas evaporation, while the narrowing member creates a specific constrained zone that prevents excessive bulging and reduces force concentration on the membrane.
3Device complexity
If no narrowing member is provided outside the outermost membrane element, then the device structure remains simple, but the separation membrane bulge is uncontrolled causing increased angle and force at the bonding portion
Solution Approach 1:
The device structure is segmented into functional zones: the main membrane element assembly allows free bulging for flow accommodation, while the narrowing member creates a separate constrained zone at the outermost end. This segmentation enables the system to simultaneously achieve simple overall structure with a localized functional addition that prevents membrane rupture without significantly increasing device complexity.
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 effectively suppresses the rupture of separation membranes on the outermost elements by limiting the bulge and reducing resistance to the upward flow, ensuring the membrane separation device operates safely and efficiently even during continuous aeration without filtration.
Implementation Method 1
An air-lift action of air bubbles supplied from the diffuser causes an upward flow in a distance between the membrane elements in which the water to be treated goes up together with the activated sludge
Implementation Method 2
the upward flow of this gas-liquid mixed phase provides aeration cleaning of the membrane surface of the separation membrane
Implementation Method 3
a gas component which has been dissolved into the treated water and then evaporated when filtered through the separation membrane
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A membrane separation device includes a plurality of membrane elements (21) each having a separation membrane (21b) arranged on front and back sides of a flat filter plate (21a), wherein the membrane elements (21) are oriented vertically and arranged in an array separated by a fixed distance such that the separation membranes (21b) of the membrane elements (21) are facing one another. A narrowing member (23a) is provided outside of a membrane element (21) arranged at the outermost position along the arrangement direction, the narrowing member (32a) being disposed at least in a vicinity of a bonding portion (21 c) of the filter plate (21 a) and the separation membrane (21 b) along the vertical direction thereof so as to be separated from the outermost membrane element (21) by a predetermined distance smaller than the fixed distance T, thereby avoiding rupture of the separation membrane provided on outer side of the outermost membrane element even if aeration is continued in a state in which the filtering operation is stopped.