Humidity-Responsive Extraction Vent Membrane for Airflow Regulation

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Solution Overview

Problem

Existing gas extraction vents fail to efficiently regulate air flow rates based on both pressure difference and humidity levels, leading to energy wastage and sensitivity to fouling, particularly in variable occupancy scenarios like bathrooms.

Innovation Solution

A gas extraction vent with a membrane that combines adjustable curvature and elasticity, utilizing a bimetallic effect from layers of hydrophobic and moisture-sensitive materials, allowing flow rate adjustment according to humidity and pressure differences, while being robust and resistant to pollutants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple elastic membrane is used for flow regulation, then the device is simple to manufacture, but it cannot account for both pressure difference and humidity variations simultaneously

Engineering Contradiction:
Improvemembrane structureVSAvoidresponse to pressure and humidity
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies composite materials by combining a hydrophobic support film with a hygroscopic sensitive film to create a membrane that responds to both pressure difference and humidity. The support film provides mechanical strength and pressure response, while the sensitive film absorbs moisture and expands in response to humidity, enabling dual-parameter regulation without complex mechanical structures

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes physical parameters of the membrane by using materials with different hygroscopic properties. The sensitive film's expansion coefficient changes with humidity absorption, causing the membrane to bend or change permeability in response to humidity levels while maintaining pressure-responsive regulation capability

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a hair hygrometer-based device is used for humidity regulation, then humidity control is achieved, but the device is sensitive to fouling by fatty particles and has complex mechanical drive mechanisms

Engineering Contradiction:
Improvehumidity regulationVSAvoidfouling by fatty particles
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical wire or braid of traditional hair hygrometers with a flexible thin film membrane that directly responds to humidity through moisture absorption. This film-based approach eliminates the mechanical components that are prone to fouling by fatty particles while maintaining humidity-responsive flow regulation capability

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent substitutes the mechanical drive mechanism of traditional hygrometers with a passive physicochemical response mechanism. Instead of using a mechanical wire that expands and drives shutters, the hygroscopic film directly modulates flow through its own expansion and bending in response to humidity, eliminating complex mechanical transmissions that are sensitive to fouling

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If a stretched wire limits membrane movement in extraction vents, then temperature and humidity regulation is possible, but the position of the membrane is exclusively dictated by vacuum until abutment occurs

Engineering Contradiction:
Improvetemperature and humidity responseVSAvoidcontinuous flow regulation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent removes the stretched wire limitation mechanism from the system. Instead of using a wire to physically limit membrane movement, the patent allows the membrane itself to naturally respond to both pressure difference and humidity variations without mechanical constraints, enabling continuous and proportional flow regulation across the full range of operating conditions

Inventive Principle:
Principle #2Taking out (Extraction)

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 enables continuous and efficient regulation of air flow rates based on humidity and pressure, reducing energy consumption and minimizing fouling, thus providing effective ventilation while maintaining air quality and reducing maintenance costs.

Implementation Method 1

utilizing a bimetallic effect from layers of hydrophobic and moisture-sensitive materials

Methodology Applied
Scientific EffectBimetallic effect: Bi-Metallic Strip

Implementation Method 2

layers of hydrophobic and moisture-sensitive materials

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

an elastic, flexible and self-supporting membrane... allowing the passage of a gas flow... the membrane bends and partially closes the openings so as to regulate the flow rate

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2604942B1Gas extraction opening with automatic adjustment and method for manufacturing such an opening
Publication Date: 2016.12.28 VTI
  • EP2604942B1 patent drawingFigure 1~3

AI summary

The mouth (1) has a flexible, self-supporting and elastic membrane (6) with a wing (7) fixed to a crosspiece of a case (2). The wing overhangingly extends relative to orifices (5) of the case in a rest position in absence of an extraction gas flow (F) to bend and partially seal the orifices. The membrane has curvature and/or elasticity variable based on moisture to oppose inflection of the membrane under effect of the flow so that flow rate of the flow traversing the mouth is simultaneously variable based on moisture of the flow and a difference in pressure on both sides of a partition (3). The membrane has a support film made of a hydrophobic material and assembled with a hygrosensible film that is made of hygrosensible material e.g. poly hexamethylene adipamide. The hydrophobic material is chosen from metal, PVC and polyethylene terephthalate. An independent claim is also included for a method for manufacturing a gas extraction mouth to be mounted in an opening of a partition.