Portable Nanoparticle Sampler Using Cyclone and Microorifice Impact
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Solution Overview
Problem
Existing nanoparticle samplers are too large and heavy, with high flow rate and pressure loss, making them unsuitable for portable use and resulting in inaccurate cutoff diameters for particle collection.
Innovation Solution
A portable nanoparticle sampler comprising a tangential flow cyclone, a multi-microorifice impactor, and a filter cassette, where the tangential flow cyclone directs airflow downward through the multi-microorifice impactor and filter cassette, reducing pressure loss and allowing precise control of cutoff diameters for accurate particle collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional NP samplers (ELPI, LPI, MOUDI, Nano-MOUDI) are used, then particle collection capability is achieved, but the samplers are too large and heavy for portable use
Solution Approach 1:
The sampler is divided into two functional stages: a cyclone separator for larger particles (RPM) and a microorifice impactor for nanoparticles. This segmentation allows each component to be optimized for its specific size range, reducing overall complexity and weight while maintaining comprehensive particle collection capability.
Solution Approach 2:
The design extracts only the essential particle separation functions from complex conventional samplers, implementing a simplified two-stage system that retains particle collection capability while eliminating unnecessary components that contribute to weight and size.
2Use of energy by moving object
If conventional NP samplers are used, then particle collection is achieved, but flow rate and pressure loss are too high to work with small portable pumps
Solution Approach 1:
The cyclone separator utilizes pneumatic principles to separate particles from airflow through centrifugal force generated by tangential flow, eliminating the need for high pressure drops. The microorifice impactor then handles nanoparticle separation at lower pressures, enabling operation with small portable pumps while maintaining collection efficiency.
Solution Approach 2:
The system changes flow parameters between stages: the cyclone operates at higher flow rates for RPM separation, then the flow is reduced for the microorifice impactor stage. This parameter optimization reduces overall pressure loss while maintaining particle collection efficiency across different size ranges.
3Measurement precision
If personal NP sampler with particle-sizing filter is used, then portability is improved, but cutoff diameter becomes inaccurate due to flow rate variations
Solution Approach 1:
The cyclone separator acts as an intermediary stage that pre-separates respirable particulate mass before the nanoparticle collection stage. This intermediary separation ensures that the microorifice impactor receives a pre-conditioned airflow with known characteristics, maintaining accurate cutoff diameter for nanoparticle measurement while preserving portability.
Solution Approach 2:
The cyclone performs preliminary separation of larger particles (RPM) before the nanoparticle sampling stage. This preliminary action stabilizes the airflow conditions entering the microorifice impactor, ensuring accurate cutoff diameter measurement for nanoparticles without compromising the portable design.
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 design enables a compact, portable sampler with precise cutoff diameters, facilitating accurate collection and analysis of nanoparticles, improving occupational health risk assessment by reducing pressure loss and maintaining precise cutoff diameters for respirable particulate mass and nanoparticles.
Implementation Method 1
a tangential flow cyclone (10), a multi-microorifice impactor (20) located below the tangential flow cyclone (10)
Implementation Method 2
The cyclone body (11) is formed of an annular portion (111), a top plate (112), and a bottom plate (113). A first chamber (114) is defined between the annular portion (111), the top plate (112), and the bottom plate (113).
Implementation Method 3
The multi-microorifice impactor includes an impaction body, a nozzle base, and an impaction plate. The nozzle base has multiple microorifice nozzles communicating with the exit and the second chamber.
Implementation Method 4
The filter cassette defines a third chamber and includes a guide passage, an outlet, and a filter. The filter is mounted inside the third chamber and partitions the third chamber into a filtration chamber and an outtake chamber.
Data Source
AI summary
A portable nanoparticle sampler for collecting respirable particulate matters and nanoparticles is composed of a tangential flow cyclone, a multi-microorifice impactor and a filter cassette. The tangential flow cyclone can remove the microparticles with cutoff aerodynamic diameter (dpa) larger than 4 μm and guide the airflow to the multi-microorifice impactor located below the cyclone. The multi-microorifice impactor includes a multi-orifice nozzle and a rotary impaction plate for enabling the microparticles with dpa from 100 nm to 4 μm to be uniformly collected on a silicone-oil-coated impaction substrate. The remnant microparticles with dpa smaller than 100 nm are collected by the filter cassette. Therefore, compared with the prior art, the portable nanoparticle sampler is characterized by low pressure loss and accurate microparticle sizing to meet the requirement of nanoparticle sampling at workplaces.