Membrane Separation Device Vibration Control

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Solution Overview

Problem

Membrane separation devices in activated sludge processes face issues due to material thermal expansion differences and volume changes, leading to vibration and reduced lifespan when submerged in biological treatment tanks, especially during temperature fluctuations.

Innovation Solution

Incorporating an elastic member within the frame body to absorb and manage dimensional changes of resin membrane modules, ensuring stable operation and reducing vibration and abrasion by maintaining a liquid-tight coupling between modules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If membrane modules are made of resin to reduce weight, then weight is reduced, but thermal expansion differences cause dimensional instability when temperature changes

Engineering Contradiction:
Improveweight of membrane modulesVSAvoiddimensional stability of membrane modules
Core Design Contradiction:
Weight of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by selecting resin materials with specific thermal expansion coefficients that match or complement the metal frame body. The resin modules are designed with controlled expansion characteristics to maintain dimensional stability within the frame across temperature variations, resolving the contradiction between weight reduction and dimensional stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite material strategies by combining resin membrane modules with metal frame body in a hybrid structure. The different materials are selected and configured to work together, with the resin providing weight reduction and the metal frame providing structural stability, thereby achieving both lightweight design and dimensional stability.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If membrane modules are made of resin, then weight is reduced, but volume expansion when submerged in water requires larger frame body

Engineering Contradiction:
Improveweight of membrane modulesVSAvoidvolume of frame body
Core Design Contradiction:
Weight of moving objectVSVolume of stationary object

Solution Approach 1:

The patent applies preliminary action by pre-submerging the resin membrane modules in water during the manufacturing process. This allows the modules to absorb water and expand to their final operational volume before being installed in the frame body. Consequently, the frame body can be designed to the exact required size without needing extra clearance for expansion, reducing overall frame volume.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses beforehand cushioning by incorporating expansion compensation mechanisms into the frame body design. These mechanisms, such as adjustable mounting structures or flexible connections, are built in advance to accommodate the volume expansion of resin modules when submerged, preventing the need for an oversized frame body.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If membrane modules are transported in tropical regions, then high temperature causes resin expansion and subsequent shrinkage, but annealing process to prevent this increases manufacturing cost

Engineering Contradiction:
Improvedimensional stability of membrane modulesVSAvoidmanufacturing cost of membrane modules
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by performing the thermal conditioning (annealing or pre-heating) during the manufacturing process itself, rather than requiring separate post-manufacturing treatment. This allows the resin modules to be pre-adjusted to their final dimensional state before assembly, eliminating the need for costly separate annealing processes and reducing overall manufacturing costs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses parameter changes by optimizing the resin material formulation and processing parameters to reduce thermal expansion sensitivity. By adjusting material composition and curing conditions, the modules achieve dimensional stability without requiring expensive post-manufacturing annealing processes, thereby reducing manufacturing costs while maintaining stability.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If membrane modules are allowed to vibrate in vertical direction, then aeration function works, but vibration causes wear and shortened lifespan

Engineering Contradiction:
Improveaeration efficiencyVSAvoidservice life of membrane modules
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent applies flexible shells and thin films by using elastic damping layers or flexible mounting structures between the membrane modules and the frame body. These flexible elements allow controlled vibration for aeration while absorbing excessive movement that would cause wear, thereby extending the service life of the membrane modules without compromising aeration efficiency.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention uses beforehand cushioning by incorporating vibration-damping materials or shock-absorbing structures in advance during the assembly of membrane modules into the frame body. These cushioning elements are positioned to mitigate vibration-induced wear before it occurs, allowing the modules to vibrate freely for aeration while protecting against damage and extending their operational lifespan.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 elastic member effectively suppresses vertical vibration and maintains a liquid-tight state, extending the operational lifespan of membrane modules and reducing material costs by minimizing the required pressing force and thickness of the rubber sheet.

Implementation Method 1

an elastic member is disposed in the frame body so as to be elastically deformed when an end portion of the frame body is closed

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

when such a membrane separation device is submerged into the biological treatment tank, the volume of the membrane modules made of resin might be increased by absorbing water in the tank

Methodology Applied
Scientific EffectWater absorption: Absorption (physical)

Implementation Method 3

the temperature inside the container rises significantly, thereby causing such a phenomenon in which resin casings constituting the liquid collection units of the membrane modules expand under a high temperature and then shrink into a size smaller than the original size when the temperature returns to a room temperature

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2666537B1Membrane separation device
Publication Date: 2020.04.15 KUBOTA CORP
  • EP2666537B1 patent drawingFigure 1
  • EP2666537B1 patent drawingFigure 2
  • EP2666537B1 patent drawingFigure 3A~3C

AI summary

A membrane separation device is provided with membrane modules (20) comprising multiple membrane elements (21), a frame body (11) accommodating the membrane modules (20) stacked in multiple stages, a stopper (14) for closing an end portion of the frame body to prevent the membrane modules (20) accommodated in the frame (11) from being released, and elastic members (15) which, arranged in a state of elastic deformation in the vertical direction in the frame (11) with the end portion of the frame (11) being closed, suppress vertical vibration of the membrane modules (20) accommodated in the frame (11), whereby making it possible to avoid vibration of the membrane modules inside the frame body even if the volume of the membrane modules accommodated in the frame body varies.