Internal-Member Exhalation Valve for Quiet Low-Pressure CO2 Release
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Solution Overview
Problem
Existing CPAP therapy devices face issues with CO2 rebreathing due to inadequate exhalation gas escape under low pressure conditions, leading to unacceptable CO2 levels, and traditional valves cause noise and discomfort due to pressure spikes and large port sizes.
Innovation Solution
The development of valves with internal members that transition between open and closed configurations based on pressure thresholds, allowing exhaled gases to escape under low pressure while maintaining a low leak under high pressure conditions, and incorporating a design that reduces noise and discomfort by using smaller ports and a compact structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If small bias flow holes are used to reduce noise, then noise is reduced, but CO2 rebreathing increases under low pressure conditions
Solution Approach 1:
The valve separates the gas flow path into two distinct routes: small bias flow holes for low-pressure exhalation (reducing noise) and large ports for high-pressure exhalation (preventing CO2 rebreathing). This segmentation allows each pathway to be optimized for its specific function without compromise
Solution Approach 2:
The valve incorporates a dynamic internal member that automatically transitions between blocking and unblocking the large ports based on pressure conditions. At low pressure, the member blocks the ports and directs flow through small holes; at high pressure, it unblocks the ports to allow rapid CO2 elimination
2Productivity
If traditional flap valves are used to control gas flow, then gas flow control is achieved, but pressure spikes and noise are generated
Solution Approach 1:
The internal member is constructed from flexible material that can deform and bend to follow the contours of the valve body interior surface. This flexibility allows progressive opening and closing of the large ports, eliminating sudden pressure spikes and associated noise while maintaining effective gas flow control
Solution Approach 2:
The internal member is designed with a curved configuration that matches the curvature of the valve body's interior surface. This curved geometry enables the member to progressively engage with and seal against the ports during closure, reducing turbulence and pressure fluctuations compared to flat flap designs
3Object-generated harmful factors
If large ports are used for exhalation, then CO2 rebreathing is reduced, but noise and discomfort increase
Solution Approach 1:
The valve dynamically adjusts the effective port size based on pressure conditions. At high pressure when CO2 elimination is critical, the large ports are fully opened. At low pressure when noise is a concern, the ports are blocked and flow is redirected through smaller holes, eliminating unnecessary noise and discomfort
Solution Approach 2:
The invention extracts the noise-generating function from the CO2 elimination function by separating them into different pathways. The large ports are dedicated solely to CO2 elimination when needed, while a separate small hole pathway handles low-pressure exhalation quietly
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 reduces CO2 rebreathing risks and noise, maintaining a consistent gas flow rate while minimizing disruption to the patient's comfort and mask seal.
Implementation Method 1
the internal member can be in 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, the at least one internal member being biased radially inward away from the interior surface. Also, the at least one internal member can be in a closed configuration that occludes the one or more ports when a gas pressure in the valve is above a threshold pressure
Data Source
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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.