Capillary Material for Humidity-Resistant Pressure Measurement

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Solution Overview

Problem

Current flow sensors used in clinical settings face accuracy issues due to humidity and water condensation, leading to signal drift and clogging of pressure measuring tubes, which affects the reliability of flow and pressure measurements in respiratory applications.

Innovation Solution

Incorporating capillary material into the pressure measuring channels to enable rapid suctioning and removal of water droplets, preventing clogging and ensuring accurate pressure and flow measurements, even under humid conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor is heated to prevent condensation, then measurement accuracy is improved, but device complexity increases due to heating elements and electrical connectors

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidheating element structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The harmful water droplets are extracted from the pressure measuring channel by the capillary material, which absorbs and removes them passively without requiring active heating elements or electrical connectors, thus maintaining measurement accuracy while reducing device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The capillary material acts as an intermediary substance between the water droplets and the pressure sensor, passively intercepting and removing water through capillary action before it can interfere with the measurement, eliminating the need for direct thermal intervention

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the inner surface is treated to reduce contact angle, then flow signal drift is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improveflow signal stabilityVSAvoidsurface treatment process
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The capillary material provides a porous structure that passively manages water through capillary action, offering a simpler manufacturing approach compared to surface treatments while achieving similar stability in flow signal by preventing water accumulation

Inventive Principle:
Principle #31Porous materials

3Reliability

If a hydrophobic porous membrane covers the orifices, then water entry is prevented, but measurement accuracy deteriorates due to pressure drop

Engineering Contradiction:
Improvewater protectionVSAvoidflow measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The capillary material serves as an intermediary that selectively interacts with water droplets through capillary action, allowing it to absorb and remove water without creating the restrictive pressure drop associated with hydrophobic membranes, thus maintaining both protection and measurement accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If a minimal purge flow is used, then water clogging is prevented, but device complexity and cost increase

Engineering Contradiction:
Improveclogging preventionVSAvoidpurge flow system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The capillary material enables the pressure measuring channel to self-clean by passively absorbing water droplets through capillary action without requiring external purge flows or additional active components, thereby preventing clogging while maintaining system simplicity and reducing cost

Inventive Principle:
Principle #25Self-service

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 capillary material effectively prevents water obstruction in pressure measuring channels, maintaining accurate flow and pressure readings for extended periods, especially in critical care environments where humidity is high.

Implementation Method 1

The pressure measuring channel is equipped with a capillary material enabling capillary suctioning of water

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2233167B1Arrangement for improving accuracy of pressure measurement and flow sensor
Publication Date: 2016.07.20 GENERAL ELECTRIC CO
  • EP2233167B1 patent drawingFigure 1~3
  • EP2233167B1 patent drawingFigure 4

AI summary

An arrangement for improving an accuracy of a pressure measurement made of a breathing gas including drops of water or humidity flowing along a flow channel is disclosed herein. The arrangement includes at least one pressure measuring channel (4) to transmit a pressure of the breathing gas flowing along the flow channel (1) to a measuring device (5) to make the pressure measurement. The pressure measuring channel is equipped with a capillary material (7) enabling capillary suctioning of water. Also a flow sensor (14) for a flow rate measurement of a breathing gas including drops of water or humidity is provided.