Respiratory Acoustic Sensor Isolation Using a Resonant Membrane

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Solution Overview

Problem

Humidified air in respiratory support devices can damage or contaminate acoustic sensors, and the sensors may release harmful particles, compromising their accuracy in detecting acoustic signals.

Innovation Solution

A respiratory support device with a conduit, acoustic generator, and sensor arrangement where a membrane covers the opening to separate airflow from the sensor, resonating at the acoustic frequency to prevent contamination while accurately detecting the signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the acoustic sensor is placed inside the conduit to detect acoustic signals, then the detection accuracy is improved, but the sensor is exposed to humidified airflow which causes contamination and damage

Engineering Contradiction:
Improveacoustic signal detection accuracyVSAvoidhumidified airflow contamination
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A membrane is introduced as an intermediary element between the acoustic sensor and the humidified airflow in the conduit. The membrane allows acoustic signals to pass through to the sensor while blocking the airflow, thus preventing contamination while maintaining detection accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a thin membrane film to separate the acoustic sensor from the airflow environment. This flexible film is permeable to acoustic waves but impermeable to the humidified air, protecting the sensor from moisture and particles while allowing accurate acoustic signal detection

Inventive Principle:
Principle #30Flexible shells and thin films

2Object-affected harmful factors

If the acoustic sensor is placed outside the conduit to avoid contamination, then the sensor is protected from humidified airflow, but the acoustic signal detection accuracy deteriorates due to signal loss

Engineering Contradiction:
Improvehumidified airflow contaminationVSAvoidacoustic signal detection accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The membrane serves as a mediator that transmits acoustic energy from the conduit to the external sensor. It allows the sensor to be positioned outside the airflow path while maintaining acoustic signal fidelity through the membrane barrier

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The membrane is designed to vibrate in response to acoustic signals passing through it, effectively transmitting the acoustic energy to the sensor outside the conduit. This mechanical vibration transfer maintains signal accuracy while keeping the sensor protected from contamination

Inventive Principle:
Principle #18Mechanical vibration

3Object-affected harmful factors

If the membrane is made rigid to block airflow effectively, then the protection against contamination is improved, but the acoustic signal transmission is blocked due to energy loss

Engineering Contradiction:
Improvecontamination protectionVSAvoidacoustic signal energy
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent uses a flexible thin film membrane that is sufficiently rigid to block humidified airflow and protect the sensor, yet thin and flexible enough to transmit acoustic vibrations effectively. This balances contamination protection with acoustic energy transmission

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The membrane parameters (thickness, material properties, tension) are optimized to achieve the right balance between airflow blocking capability and acoustic signal transmission. By adjusting these parameters, the system maintains both protection and signal fidelity

Inventive Principle:
Principle #35Parameter changes

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

Prevents contamination between the acoustic sensor and airflow, allowing accurate detection of acoustic signals without exposing the sensor to harmful particles, ensuring reliable operation.

Implementation Method 1

The membrane is adapted to resonate at the acoustic frequency

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4675238A1Respiratory support device and method for detecting an acoustic signal
Publication Date: 2026.01.07 KONINKLIJKE PHILIPS NV
  • EP4675238A1 patent drawingFigure 1~2
  • EP4675238A1 patent drawingFigure 3~4
  • EP4675238A1 patent drawingFigure 5~6

AI summary

There is provided a respiratory support device for providing pressurized air to a subject. The respiratory support device comprises a conduit, an acoustic generator, and an acoustic sensor. The conduit is for conveying an airflow. The conduit has an opening. The acoustic generator is adapted to generate an acoustic signal in the conduit at an acoustic frequency. The acoustic sensor is arranged outside the conduit. The acoustic sensor is adapted to generate a sensor signal representative of the acoustic signal. The respiratory support device comprises a membrane arranged to cover the opening to separate the acoustic sensor and the airflow from each other. The membrane is adapted to resonate at the acoustic frequency.