Nasal Seal Adjustment in CPAP Masks for Leak Control
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Solution Overview
Problem
Full face masks used for positive pressure respiratory therapy often cause discomfort and pressure sores due to elevated pressure on the nasal bridge, while loose fitting masks lead to air leakage, particularly around the tear ducts and nasal bridge.
Innovation Solution
A mask assembly with a seal adjustment mechanism that applies lateral compressive force to the nasal bone, reducing pressure on the nasal bridge and minimizing air leakage, using various mechanisms such as dials, cages, lift bars, malleable strips, and scissor arms to control seal compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the headgear is tightened to reduce leakage, then the seal effectiveness is improved, but the pressure on the nasal bridge increases causing discomfort and pressure sores
Solution Approach 1:
The mask seal is divided into multiple independent sections: a nasal seal portion with first and second seal sections that can be independently adjusted, and a oral seal portion. This segmentation allows the nasal bridge area to be sealed with reduced pressure by distributing the sealing function across multiple sections rather than requiring uniform high pressure across the entire nasal bridge.
Solution Approach 2:
Different portions of the mask seal have different structural properties optimized for their specific functions. The first seal section has a first cross-sectional shape optimized for sealing the nasal bone area, while the second seal section has a second cross-sectional shape optimized for sealing the cheek area. This local optimization allows effective sealing without excessive pressure on the nasal bridge.
2Object-affected harmful factors
If the headgear is loosened to improve patient comfort, then the pressure on the nasal bridge is reduced, but air leakage occurs around the tear ducts and nasal bridge
Solution Approach 1:
The nasal seal portion is designed to be movable relative to the mask base, allowing it to dynamically adapt to the patient's facial contours. The seal can shift position to maintain optimal contact with the nasal bone and cheek areas, ensuring effective sealing even when the overall headgear tension is reduced for comfort.
Solution Approach 2:
The seal adjustment mechanism provides an additional degree of freedom for seal positioning beyond simple tightening/loosening of the headgear. By allowing lateral movement of the nasal seal portion independent of the oral seal portion, the system can achieve effective sealing at lower overall pressures.
3Device complexity
If a single seal circumscribes both the nose and mouth, then the mask structure is simplified, but the seal cannot provide targeted compression to prevent leakage around the tear ducts
Solution Approach 1:
The nasal seal portion is divided into at least two separate seal sections: a first seal section that targets the nasal bone and tear duct area, and a second seal section that targets the cheek area. This segmentation allows each section to be independently positioned and compressed to prevent leakage around the tear ducts, while still being part of an integrated nasal seal assembly.
4Reliability
If the mask seal is compressed uniformly, then the seal effectiveness is improved, but the pressure is concentrated on the nasal bridge causing discomfort
Solution Approach 1:
The mask seal employs different cross-sectional shapes at different locations to achieve non-uniform pressure distribution. The first seal section has a first cross-sectional shape that concentrates compression on the nasal bone and tear duct area, while the second seal section has a second cross-sectional shape that distributes pressure on the cheek area. This allows effective sealing without concentrating excessive pressure on the nasal bridge.
Solution Approach 2:
Instead of applying compression from the front (nasal bridge area) as in conventional masks, this design applies compression primarily from the lateral sides (cheek areas) and from below (nasal bone area). The seal sections are positioned to compress the facial contours from multiple angles, inverting the traditional compression approach to relieve nasal bridge pressure while maintaining seal effectiveness.
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 provides improved comfort by reducing pressure on the nasal bridge and effectively seals around the tear ducts, minimizing air leakage and eye dryness during use.
Implementation Method 1
a seal adjustment mechanism coupled to the mask base and configured to compress the mask seal primarily in a lateral direction across a width of the mask assembly
Data Source
AI summary
An interface for positive pressure therapy includes a mask assembly and a headgear assembly. The mask assembly comprises a mask seal that is adapted to underlie the nose. The mask seal extends up the lateral sides of the nose. The mask seal has a primary seal below the nose and a secondary seal alongside the nose.