Eccentric Valve Membrane Fixing for Respirator Flow Resistance

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Solution Overview

Problem

Existing directional valves in respirators face high flow resistance due to central membrane attachment and leakage issues with one-sided attachment designs, especially in humid environments where adhesion occurs, affecting tightness and flow efficiency.

Innovation Solution

A directional valve with a circular or oval valve membrane fixed eccentrically between 8% and 25% of its axis length, utilizing a Y-shaped fixing lug for secure attachment and reduced flow resistance, preventing adhesion from moisture and ensuring mechanical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the valve membrane is centrally attached to the valve seat, then the valve structure is simple and stable, but the flow resistance becomes relatively high

Engineering Contradiction:
Improvevalve structure simplicityVSAvoidflow resistance
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent applies asymmetry by moving the fixing lug from the center to an off-center position on the valve seat. This asymmetric arrangement allows the valve membrane to deflect more freely across the sealing surface, increasing the effective flow area and reducing flow resistance while maintaining structural stability through the strategically positioned fixing point.

Inventive Principle:
Principle #4Asymmetry

2Loss of energy

If the valve membrane is attached to one side of the valve seat, then the flow resistance decreases, but leakage increases and adhesion occurs in humid environments

Engineering Contradiction:
Improveflow resistanceVSAvoidvalve tightness
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent changes the positional parameter of the fixing lug from centered to off-center, specifically positioning it within 10-30% of the radius from the center. This parameter optimization allows the valve membrane to maintain better contact with the sealing surface, preventing leakage and adhesion while still achieving lower flow resistance compared to central attachment.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If the valve membrane is off-center fixed, then the flow resistance drops significantly, but the valve membrane may have reduced mechanical stability

Engineering Contradiction:
Improveflow resistanceVSAvoidvalve membrane stability
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The patent applies partial fixation by positioning the fixing lug off-center rather than at the center, providing just enough mechanical anchoring to maintain stability while allowing the majority of the valve membrane surface to deflect freely. This partial fixation approach achieves the optimal balance between stability and flow efficiency.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2570156B1Directional valve and respirator mask with a directional valve
Publication Date: 2018.07.11 DRAGER SAFETY AG & CO KAAA
  • EP2570156B1 patent drawingFigure 1
  • EP2570156B1 patent drawingFigure 2
  • EP2570156B1 patent drawingFigure 3

AI summary

The valve has a fixing lug arranged at a valve housing for fixing a valve membrane in a valve seat (1) and for supporting sealing of a flat sealing surface (2) by the valve membrane during an inspiration phase. The fixing lug is arranged between a surface center of the valve membrane and an edge of the valve membrane such that an entire circumferential area of the valve membrane is lifted-out from the sealing surface during an expiration phase, and a flow resistance for an expired air, which is low in relation to a central arrangement of the fixing lug is adjusted. An independent claim is also included for a breathing mask.