Aerosol Delivery Measurement Using Optical Detection and Segmented Filtration

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Solution Overview

Problem

Current methods for determining aerosol delivery and absorption/adsorption of liquids on aerosol particles are limited by the need for frequent filter replacements, delayed measurement results, and modification of particles during chemical analysis, particularly for large aerosol amounts and small tidal volumes, such as those required for infants and neonates.

Innovation Solution

A device comprising a collecting unit with a filter, a measurement volume for interaction with a light beam, and an optical measurement unit to generate signals for determining aerosol delivery and absorption/adsorption, allowing real-time, quantitative measurement of aerosol delivery and liquid absorption/adsorption without modifying the particles, using a conversion function derived from gravimetric and optical data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If flat filters are used to limit dead volume to 10% or less of tidal volume, then measurement accuracy for small tidal volumes is improved, but filter capacity is reduced requiring frequent replacements

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidfilter capacity

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent divides the filtering function into two separate components: a flat filter for accurate small tidal volume measurement and a large capacity filter for capturing total aerosol delivery. This segmentation allows each filter to be optimized for its specific function, resolving the contradiction between measurement accuracy and filter capacity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a flow splitter as an intermediary device that divides the aerosol stream into two paths: one through the flat filter for measurement and another through the large capacity filter for total collection. This intermediary enables both filters to operate simultaneously without interfering with each other's function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If quantitative chemical analysis is performed on collected aerosol, then measurement accuracy is improved, but time for delivery of measurement results is increased

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidtime for measurement results

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the traditional quantitative chemical analysis method with an optical measurement system using light scattering or absorption. This substitution eliminates the time-consuming chemical analysis step while providing real-time measurement of aerosol delivery, resolving the contradiction between measurement accuracy and time for results.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If gravimetric determination is used for humidified aerosols, then measurement accuracy is improved, but additional conditioning of filters is required causing delay

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidfilter conditioning complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces gravimetric determination with optical measurement that does not require filter conditioning. The optical system measures aerosol properties directly in the gas phase without needing to collect and weigh particles on a filter, thereby eliminating the complex conditioning steps required for humidified aerosols.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables simple, real-time determination of aerosol delivery and absorption/adsorption for both large and small tidal volumes, reducing the need for frequent filter replacements and enabling immediate measurement results, applicable to adult and pediatric patients.

Implementation Method 1

at least one measurement volume which is designed for an interaction of at least one light beam with the aerosol particles carried by the aerosol stream and passing through the measurement volume

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 2

interaction of at least one light beam with the aerosol particles carried by the aerosol stream and passing through the measurement volume

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS11992606B2Device and method for determining an aerosol delivery

Publication Date: 2024.05.28 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

A device for determining delivery of an aerosol stream has a collector having a filter for collecting aerosol particles in the aerosol stream, a first fluid connection point connectable to an aerosol generator, and a second fluid connection point connectable to a breathing simulator for simulating tidal breathing, at least one measurement volume for an interaction of at least one light beam with the aerosol particles passing through the measurement volume, at least one optical measurement unit for generating at least one optical measurement signal depending on the interaction of the at least one light beam with the aerosol particles passing the measurement volume, and at least one evaluation unit for determining the aerosol delivery of the aerosol stream from the at least one optical measurement signal. A method determines an absorption and/or adsorption of a liquid on aerosol particles.