Pressure-Threshold Valve Member for Quiet CO2 Flushing
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Solution Overview
Problem
Existing CPAP therapy systems face issues with CO2 rebreathing due to inadequate exhalation gas venting, particularly under low pressure conditions, leading to noise and discomfort, and traditional valves are cumbersome and noisy.
Innovation Solution
The development of valves with internal members that transition between open and closed configurations based on pressure thresholds, allowing for controlled gas flow and venting, reducing noise and discomfort while maintaining effective CO2 flushing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional valves are used for gas venting, then CO2 rebreathing can be reduced, but the valve becomes noisy and cumbersome
Solution Approach 1:
The valve incorporates a movable internal member that dynamically transitions between open and closed positions based on pressure differential. During inhalation, the member opens to allow gas venting; during exhalation, it closes to prevent CO2 rebreathing. This dynamic operation reduces noise compared to traditional constantly-open valves while maintaining effective CO2 flushing.
Solution Approach 2:
The valve operation is controlled by pressure parameter changes in the respiratory circuit. When pressure exceeds a threshold during inhalation, the internal member opens; when pressure drops during exhalation, the member closes. This pressure-based control mechanism enables silent, automated valve operation that adapts to respiratory cycles without mechanical noise.
2Object-affected harmful factors
If larger ports are used for gas venting, then CO2 rebreathing is reduced, but noise increases
Solution Approach 1:
The valve uses a movable internal member that dynamically adjusts the port opening size based on respiratory phase. During inhalation, the member opens to reveal larger ports for effective CO2 venting; during exhalation, the member closes the ports to eliminate noise and prevent CO2 rebreathing. This dynamic size adjustment resolves the contradiction between large port area for CO2 removal and small port area for noise reduction.
3Object-affected harmful factors
If the valve is positioned close to the patient interface, then CO2 rebreathing is minimized, but mask displacement risk increases
Solution Approach 1:
The valve is segmented into modular components: a compact valve body housing the internal member mechanism, and separate attachment interfaces for the patient interface and tubing. This segmentation allows the valve to be positioned close to the patient interface (minimizing dead space and CO2 rebreathing) while the modular design prevents excessive weight or bulk from displacing the mask. The lightweight internal member further reduces impact on mask stability.
4Speed
If the internal member transitions quickly between positions, then response time is improved, but noise increases
Solution Approach 1:
The valve incorporates damping elements and friction mechanisms that provide controlled resistance to the internal member's motion. This beforehand cushioning effect prevents sudden, noisy impacts when the member transitions between open and closed positions, while still maintaining sufficiently fast response time to track respiratory cycles. The cushioning mechanism absorbs transition shocks that would otherwise generate noise.
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 solution effectively mitigates CO2 rebreathing, reduces noise, and minimizes valve length to prevent mask displacement, enhancing patient comfort and therapy efficacy.
Implementation Method 1
the internal member having a closed configuration that occludes the one or more ports when a gas pressure in the valve is above a threshold pressure and an open configuration that allows gas to pass from the passageway to the environment when the gas pressure in the valve is at or below a threshold pressure
Data Source
AI summary
A valve with an internal member is disclosed which allows exhaled carbon dioxide to escape from a breathing circuit when the circuit gas pressure drops below a threshold pressure. The valve operates by occluding one or more ports under a relatively high pressure and opening the one or more ports under a relatively low pressure. The internal member is attached to the body of the valve at two or more locations on the internal member. The internal member moves in a direction perpendicular to the gas flow through the valve.