Permeation Test Cell with Perpendicular Convection and Sorbent Capture
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Solution Overview
Problem
Existing methods for permeation testing of protective materials against low volatility chemical warfare agents like VX and Novichokes are inaccurate and costly, particularly in convective flow mode, due to incomplete vaporization of contaminants and the need for large sample sizes, which pose a higher exposure risk.
Innovation Solution
A permeation test cell design with a gaseous stream perpendicular to the test sample, sorbent material in the lower body, and quality control measures to ensure accurate quantification of permeation density, using a smaller sample size and minimizing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional permeation testing methods (TOP 08-2-501) are used with large sample sizes, then measurement precision is improved, but exposure risk and cost increase
Solution Approach 1:
The patent employs a permeation test cell with a test sample in the form of a thin film or membrane that separates the upper and lower bodies. This thin film configuration allows for reduced sample size while maintaining measurement precision, thereby reducing chemical exposure risk during testing of protective materials
Solution Approach 2:
The patent introduces a sorbent material as an intermediary substance in the lower body to capture and concentrate permeated chemicals. This mediator enables accurate measurement of permeation density with smaller sample sizes by enhancing the detection capability through chemical concentration, thus reducing exposure risk
2Adaptability or versatility
If convective flow mode is used for permeation testing, then realism of test conditions is improved, but vaporization completeness deteriorates for low volatility chemicals
Solution Approach 1:
The patent modifies the parameters of convective flow by controlling gas flow rate, temperature, and direction through the test cell. By optimizing these parameters, the system achieves both realistic test conditions and complete vaporization of low volatility chemicals, resolving the contradiction between realism and measurement precision
Solution Approach 2:
The patent applies preliminary heating or pre-vaporization of contaminants before the main permeation test in convective flow mode. This preliminary action ensures complete vaporization of low volatility chemicals while maintaining the realism of convective flow conditions during the actual permeation measurement
3Measurement precision
If sorbent material is used in lower body for contaminant accumulation, then quantification accuracy is improved, but device complexity increases
Solution Approach 1:
The lower body of the test cell is designed to serve multiple functions: it acts as both the collection chamber for permeated chemicals and the housing for sorbent material. This multi-functional design improves quantification accuracy while minimizing the increase in device complexity by avoiding separate dedicated components
4Measurement precision
If gaseous stream is passed perpendicular to test sample, then permeation evaluation accuracy is improved, but energy consumption increases
Solution Approach 1:
The patent applies partial convective flow by using a gaseous stream perpendicular to the test sample only during specific phases of the permeation test, rather than continuously. This partial action maintains measurement precision while reducing overall energy consumption of the gaseous stream system
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 method provides accurate, cost-effective quantification of permeation resistance of protective materials under realistic conditions, reducing operational costs and exposure risks while ensuring high confidence in protective capabilities.
Implementation Method 1
a gaseous stream may be passed from the upper cell cap to the lower cell cap in a direction perpendicular to a surface of the test sample, for assisting permeation of the contaminant through the test sample
Implementation Method 2
A cavity may be provided in the lower body to store a sorbent material for accumulation of the contaminant permeated through the test sample
Data Source
AI summary
Present disclosure relates to a permeation test cell for permeation testing of materials against chemicals, and comprises an upper body provided with an upper cell cap having a first vent and a lower body provided with a lower cell cap having a second vent. A test sample is disposed in the permeation test cell. A liquid contaminant is spiked onto test sample. After contamination of the test sample, a gaseous stream is passed through the upper cell cap and the lower cell cap in a direction perpendicular to a surface of the test sample, for assisting permeation of the contaminant through the test sample. The lower cell cap is provided with a cavity to store a sorbent material for accumulation of the permeated contaminant in the sorbent material.