Composite Diaphragm for CBRN Protection and Pressure Response
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Solution Overview
Problem
Conventional lung demand valves are complex and costly when adapted for use in CBRN environments due to the permeability of silicone diaphragms, which allows hazardous agents to penetrate, necessitating additional layers and mechanisms to prevent inhalation of toxic gases.
Innovation Solution
A composite diaphragm with a CBRN barrier layer made of polyvinylidene fluoride (PVDF) and a resilient layer, such as silicone, that restricts the permeation of hazardous agents while maintaining responsiveness to pressure changes, allowing the diaphragm to be both resistant to CBRN agents and deformable for proper gas supply control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicone diaphragm is used in a lung demand valve for CBRN environments, then the diaphragm is permeable to CBRN agents, but using additional impermeable layers increases device complexity and cost
Solution Approach 1:
The patent applies composite materials by combining an elastomeric layer (providing resilience and pressure responsiveness) with an impermeable CBRN barrier layer (preventing penetration of hazardous agents). This composite structure achieves both protection against CBRN agents and operational functionality without requiring complex multi-component systems.
Solution Approach 2:
The patent applies local quality by creating a diaphragm where different regions have different properties: the elastomeric layer provides mechanical compliance and pressure sensitivity, while the CBRN barrier layer provides chemical protection. This localized functional differentiation allows the single diaphragm to simultaneously achieve protection and operational response.
2Reliability
If an impermeable CBRN barrier layer is added to prevent agent permeation, then protection against hazardous agents is improved, but the diaphragm's responsiveness to pressure changes deteriorates
Solution Approach 1:
The composite diaphragm structure allows the elastomeric layer to maintain pressure responsiveness while the CBRN barrier layer provides protection. The elastomeric layer's inherent flexibility and elastic properties ensure that the diaphragm can still deform in response to pressure changes despite the presence of the impermeable barrier layer.
Solution Approach 2:
By assigning different functional properties to different layers of the diaphragm, the elastomeric layer handles the mechanical response to pressure changes while the CBRN barrier layer handles the chemical protection function. This functional separation allows both protection and operational responsiveness to be achieved simultaneously.
3Reliability
If a composite diaphragm with CBRN barrier layer is used, then permeation of hazardous agents is restricted, but manufacturing complexity increases
Solution Approach 1:
The patent addresses manufacturing complexity by describing a laminated composite structure where the elastomeric layer and CBRN barrier layer are bonded together. This approach, while creating a composite material, uses a straightforward lamination process that combines two relatively simple layers rather than requiring complex multi-step manufacturing procedures.
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 composite diaphragm effectively prevents the inhalation of CBRN agents, ensuring user safety while maintaining operational efficiency over a wide temperature range and complying with relevant safety standards, thereby simplifying the design and reducing costs compared to existing solutions.
Implementation Method 1
a CBRN (or barrier) layer which is sufficiently resistant to the permeation of at least some CBRN (or hazardous) agents
Implementation Method 2
a resilient layer which is resiliently deformable; wherein the resilient layer is arranged to allow the diaphragm to be resiliently deformed
Data Source
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AI summary
A diaphragm 18 for a lung demand valve 10, comprises a CBRN layer 58 which is sufficiently resistant to the permeation of at least some CBRN agents and a resilient layer 60 which is resiliently deformable. The CRBN layer 58 is arranged to restrict the permeation of at least some CBRN agents through the diaphragm 18, and the resilient layer 60 is arranged to allow the diaphragm 18 to be resiliently deformed.