Expulsion Liner One-Way Valve Prosthetic Moisture Management
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Solution Overview
Problem
Prosthetic liners often trap moisture against the skin, leading to potential skin irritation and detachment issues due to the non-permeable environment created by vacuum-assisted socket systems, which can be detrimental to amputee limb health.
Innovation Solution
An expulsion liner with an elongated elastomeric tube and a one-way valve at the distal end that allows controlled expulsion of moisture and air, using a duckbill valve or similar mechanism with a cracking pressure of about 0.2 psi, ensuring the residual limb remains dry during ambulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum-assisted socket systems are used to secure the prosthesis, then prosthetic device stability is improved, but moisture accumulates against the skin causing skin irritation and potential detachment
Solution Approach 1:
The liner incorporates a one-way valve mechanism that functions as a controlled porous element, allowing moisture vapor to escape from the interior space while preventing external contaminants from entering. This resolves the contradiction by enabling selective permeability - maintaining the sealed environment needed for vacuum stability while providing an escape path for accumulated moisture.
Solution Approach 2:
The invention extracts the harmful moisture and air from the interior space through the one-way valve. The valve selectively removes accumulated perspiration and air bubbles while maintaining the vacuum seal for prosthetic attachment, thereby eliminating the harmful effect without compromising the stabilizing function.
2Reliability
If non-permeable materials are used to create vacuum seal, then prosthetic suspension is improved, but limb health deteriorates due to trapped perspiration
Solution Approach 1:
The one-way valve acts as a controlled porous element within the otherwise non-permeable liner material. It provides selective permeability that allows perspiration vapor to escape while maintaining the vacuum seal integrity for prosthetic suspension, thus resolving the contradiction between seal integrity and moisture management.
Solution Approach 2:
The one-way valve serves as an intermediary element between the sealed interior space and the external environment. It mediates the conflict between needing a sealed environment for suspension and needing moisture escape for health, by selectively allowing moisture vapor passage while blocking air and contaminants.
3Reliability
If moisture accumulates in the liner, then comfort deteriorates, but attachment reliability may be compromised due to loss of skin-linkage
Solution Approach 1:
The one-way valve continuously extracts accumulated moisture and air from the interior space, preventing moisture buildup that would cause discomfort and potential skin detachment. This maintains both comfort and attachment reliability by keeping the skin-dry interface intact.
Solution Approach 2:
The valve provides continuous moisture expulsion functionality throughout the wear period, maintaining constant comfort and attachment reliability. The continuous operation prevents intermittent moisture buildup that would otherwise compromise comfort and skin linkage.
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 moisture accumulation, preventing skin irritation and maintaining a secure attachment between the liner and skin, thereby enhancing prosthetic device stability and comfort for amputees.
Implementation Method 1
A one-way valve is positioned within the closed distal end and provides controlled fluid communication between the interior space and an external environment. The one-way valve may be configured to allow the weight of a user, via the residual limb, to expel moisture and air from the interior space out to the external environment.
Implementation Method 2
The elastomer forming the liner frictionally engages and remains attached to the skin of a residual limb. Various silicone rubber or elastomer materials are used for suspension liners. Such elastomer materials having an appropriate hardness/softness, elongation, tensile, and other properties.
Implementation Method 3
The elastomer forming the liner frictionally engages and remains attached to the skin of a residual limb so that the limb is retained within the prosthetic socket.
Data Source
AI summary
The expulsion liner is for use with a prosthetic device to be secured to a residual limb. The expulsion liner includes an elongated elastomeric tube having a closed distal end and an open proximal end, and defining an interior space configured to receive the residual limb. A one-way valve is positioned within the closed distal end and provides controlled fluid communication between the interior space and an external environment. The one-way valve may be configured to allow the weight of a user, via the residual limb, to expel moisture and air from the interior space out to the external environment.