Diffusive Sampling Device with Interchangeable Porous Membranes
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Solution Overview
Problem
Existing diffusive sampling devices are limited by design for specific applications, leading to issues such as low or high sampling rates, saturation, contamination, and difficulty in handling and transporting samples, which affects their operational performance and versatility.
Innovation Solution
A compact, versatile diffusive sampling device with a porous hollow diffusion body and adsorbent body, featuring a cylindrical shape with radial and axial adsorption capabilities, allowing for easy assembly, manipulation, and interchangeability of diffusion bodies with varying porosities and materials, along with a removable design for cleaning and compatibility with conventional desorption equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diffusive samplers are designed for specific applications with fixed sampling rates, then sampling performance is optimized for particular conditions, but versatility and adaptability to different sampling conditions are reduced
Solution Approach 1:
The sampler design incorporates interchangeable diffusion membranes with different porosity values (e.g., 10%, 20%, 30%, 40%) that can be selected based on the specific analyte and sampling conditions. The support body and housing structure remain universal, allowing the same base design to function across multiple applications by simply changing the membrane component.
Solution Approach 2:
The diffusion membrane is designed as a separate, removable component that can be independently replaced. This segmentation allows users to swap membranes without replacing the entire sampler, enabling adaptation to different sampling requirements while maintaining the core device structure.
2Reliability
If diffusion path length is increased to reduce sampling rate and prevent saturation, then adsorbent saturation is reduced, but device length and complexity increase
Solution Approach 1:
Instead of uniformly increasing the diffusion path length throughout the entire device, the invention modifies the local property of the diffusion membrane by adjusting its porosity. This allows control of the sampling rate through membrane selection rather than through device geometry changes, maintaining a compact form factor.
3Measurement precision
If sampling rate is increased to achieve higher sensitivity and shorter sampling times, then detection sensitivity improves, but adsorbent saturation occurs more quickly
Solution Approach 1:
The system provides dynamic adjustability of the sampling rate by allowing users to select different diffusion membranes based on the expected analyte concentration and desired sampling duration. High porosity membranes (e.g., 40%) are used for low concentrations requiring high sensitivity, while low porosity membranes (e.g., 10%) are used for high concentrations requiring longer sampling periods.
4Ease of manufacture
If diffusion membranes are made reusable and exposed to ambient conditions, then cost is reduced, but membranes deteriorate over time and become contaminated with graphitized adsorbent
Solution Approach 1:
The diffusion membranes are designed as disposable components that can be easily replaced. After use, membranes are discarded rather than cleaned and reused, eliminating contamination issues while keeping the overall system cost-effective due to the simple, reusable support body and housing structure.
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 device provides enhanced sensitivity, ease of use, and adaptability for various sampling conditions, reducing manufacturing costs and blank levels, while maintaining high sensitivity and reproducibility, and is suitable for both stationary and mobile applications.
Implementation Method 1
Passive diffusive sampling relies on the diffusion of analytes through a diffusive surface onto an adsorbent
Implementation Method 2
the analyte be collected owing to the concentration gradient between the bulk ambient air concentration and a retention medium (i.e. solid adsorbent, liquid or gel absorbent)
Data Source
AI summary
A diffusive sampling device (1) comprises a porous hollow diffusion body (3) removably held on a support body (2), an adsorbent body (4) located inside said diffusion body (3), wherein the hollow diffusion body (3) has a cylindrically shaped wall with an upper section comprising a closed upper end and a distal lower section comprising an open lower end and wherein the diffusion body (3) is held on the support body (2) by means of one or more o-rings (7) fixed to its lower section, wherein the adsorbent body (4) is kept in a predetermined place inside the upper section of the diffusion body (3) by way of an elastic means, such as a spring (6). The use of such devices as well as a method for air sampling and monitoring.