Inhaler Flow Profile via Acoustic Peak Frequency

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Solution Overview

Problem

Existing methods for measuring the flow profile of inhalation devices are limited by variations in the propagation path and sensitivity of microphones, which affect the accuracy of flow rate estimation, and aim to minimize disturbance to the user while requiring minimal additional apparatus.

Innovation Solution

Measuring acoustic emissions induced by inhalation flow through the inhalation device, detecting peak frequencies and acoustic power, and generating a flow profile using a look-up table relationship between these measurements and flow rates, independent of the proximity to the measuring device, allowing for accurate determination of flow profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a high quality repeatable microphone is attached to the inhaler to reduce variations in propagation path and coupling, then measurement precision is improved, but device complexity and ease of operation worsen

Engineering Contradiction:

Improveflow rate estimate accuracyVSAvoidmicrophone attachment requirements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts the measurement function from the inhaler device itself by using a separate mobile device (smartphone, tablet, or computer) with its own microphone to capture acoustic emissions. This removes the need to attach additional microphones to the inhaler, simplifying the overall device configuration while maintaining measurement capability through digital signal processing and calibration techniques.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary calibration process that establishes a relationship between acoustic power measurements and flow rates without requiring direct physical coupling between the microphone and inhaler. The calibration table acts as a mediator that translates variable acoustic measurements into accurate flow rate estimates, compensating for propagation path variations without requiring fixed microphone attachment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If acoustic power measurements are used to estimate flow rate with a calibration table, then measurement precision is improved, but reliability worsens due to variations in propagation path and microphone sensitivity

Engineering Contradiction:

Improveflow rate estimationVSAvoidconsistency across different microphones and positions

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The invention changes the measurement parameter from absolute acoustic power to spectral peak frequency of the swirl tone. The spectral peak frequency is inherently more reliable because it is independent of microphone sensitivity and propagation path losses. By focusing on the frequency characteristic rather than amplitude, the system achieves consistent flow rate measurements across different microphones, positions, and recording conditions.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If minimal modification to the inhaler is required, then ease of operation is improved, but measurement precision worsens due to uncontrolled propagation path

Engineering Contradiction:

Improveuser disturbanceVSAvoidflow rate accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The invention replaces the mechanical approach of attaching microphones directly to the inhaler with a digital/acoustic approach. A mobile device records acoustic emissions from the inhaler at a distance, and signal processing algorithms extract flow rate information. This substitution eliminates the need for physical modification of the inhaler while maintaining measurement precision through spectral analysis of the characteristic swirl tone frequency.

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

This method provides accurate and minimally invasive flow profile measurements for inhalation devices, independent of microphone proximity, simplifying calibration and reducing the need for additional modifications, while maintaining high accuracy across a range of flow rates.

Implementation Method 1

measuring acoustic emissions induced by inhalation flow through the inhalation device

Methodology Applied

Scientific EffectAcoustic emissions: Acoustic Emission

Implementation Method 2

detecting two or more peak frequencies in the measured acoustic emissions; generating a flow profile based on the detected peak frequencies

Methodology Applied

Scientific EffectSpectral peak detection:

Data Source

PatentUS11266347B2Apparatus and method for producing a flow profile

Publication Date: 2022.03.08 NOVARTIS AG

AI summary

A method for generating a flow profile of an inhalation device is described. The method comprises the step of measuring acoustic emissions induced by inhalation flow through the inhalation device. The method further comprises the step of detecting peak frequencies in the measured acoustic emissions and generating a flow profile based on the detected peak frequencies. A corresponding device is also described.