CPAP Device Noise Reduction via Localized Sound Absorbing Recess
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Solution Overview
Problem
CPAP devices generate noise due to airflow, which disrupts the sleep of patients, and existing noise reduction methods increase the device's size.
Innovation Solution
A CPAP device design featuring a sound-absorbing material with a recess in the flow channel, where the recess's diameter is greater than the fan's air inlet but less than or equal to the flow channel's width, to minimize noise by smoothing airflow and reducing pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a sound absorbing material is provided in the flow channel to reduce noise from airflow, then noise levels decrease, but the device size increases
Solution Approach 1:
The sound absorbing material is not provided throughout the entire flow channel, but only in a specific local region where the airflow direction changes. This localized application reduces noise at the critical location while minimizing the overall volume occupied by the sound absorbing material, thus resolving the contradiction between noise reduction and device size reduction.
Solution Approach 2:
The invention utilizes the depth dimension of the flow channel to position the sound absorbing material strategically. By placing the material at a specific depth position where the airflow direction changes, the design achieves effective noise reduction without requiring additional lateral space, thereby maintaining a compact device footprint.
2Volume of moving object
If the fan air inlet is disposed orthogonal to the flow channel to reduce device size, then device compactness improves, but noise increases due to abrupt airflow direction change
Solution Approach 1:
The orthogonal arrangement of the fan air inlet to the flow channel is maintained for compactness, but a sound absorbing material is strategically placed only in the specific region where the airflow direction changes. This localized treatment addresses the noise problem at the critical location without requiring a change in the overall compact orthogonal layout.
Solution Approach 2:
The sound absorbing material acts as an intermediary element between the flow channel and the fan air inlet. It mediates the abrupt airflow direction change by absorbing the shock and turbulence generated by the orthogonal transition, thereby reducing noise while allowing the compact orthogonal configuration to be maintained.
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 design effectively reduces noise levels to 33 dBA or less, specifically targeting frequencies that disturb sleep, without increasing the device's size.
Implementation Method 1
a sound absorbing material is provided in a flow channel which guides air to the fan
Data Source
AI summary
According to one embodiment, a CPAP device includes a housing, a fan, and a sound absorbing material. The housing has a first air inlet and a first air outlet, and a flow channel guiding air sucked through the first air inlet to the first air outlet. The fan has a second air inlet and a second air outlet, the second air inlet is disposed in the direction intersecting the flow channel, and the second air outlet is disposed in the direction along the flow channel. The sound absorbing material is provided with a recess constituting a part of the flow channel and facing the second air inlet of the fan, the recess having a diameter which is greater than a diameter of the second air inlet of the fan and which is equal to or smaller than the width of the flow channel.