Selective Aerosol Purification via Segmented Electrostatic Charging

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Solution Overview

Problem

Current methods fail to simultaneously and selectively collect particles of different dimensions, such as nanoparticles and micron-sized particles, from aerosols, which is crucial for assessing exposure and contamination, particularly in industrial and environmental settings.

Innovation Solution

An electrostatic collection method that decouples the charging mechanisms of unipolar ion diffusion and corona discharge to charge and collect finest and largest particles separately on distinct substrates, utilizing a cylindrical conduit with specific electrode configurations to generate electric fields without and with corona effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single electrostatic collection method is used, then collection efficiency is improved, but selectivity between different particle sizes deteriorates

Engineering Contradiction:
Improvecollection efficiencyVSAvoidparticle size separation precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent divides the collection system into multiple independent collection zones (first collection substrate and second collection substrate), each optimized for different particle size ranges. The diffusion charger and corona discharge charger are also segmented into separate charging zones, allowing selective charging and collection of finest particles versus largest particles simultaneously

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different charging mechanisms (diffusion charging vs. corona discharge) are applied locally to different particle populations based on their size characteristics. The diffusion charger with unipolar ions is positioned to primarily charge finest particles, while the corona discharge electrode charges largest particles, creating local quality differences in charging efficiency across the aerosol stream

Inventive Principle:
Principle #3Local quality

2Measurement precision

If diffusion charging with unipolar ions is used, then charging of finest particles is improved, but charging of largest particles deteriorates

Engineering Contradiction:
Improvefinest particle charging efficiencyVSAvoidlargest particle charging efficiency
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent merges two different charging mechanisms (diffusion charging and corona discharge) into a single integrated system that processes aerosols simultaneously. This combination allows the system to overcome the limitations of each individual charging method by providing both fine particle optimization and coarse particle coverage through parallel charging pathways

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If corona discharge is used, then charging of largest particles is improved, but charging of finest particles deteriorates

Engineering Contradiction:
Improvelargest particle charging efficiencyVSAvoidfinest particle charging efficiency
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The charging system is segmented into two distinct charging regions: a diffusion charging region with unipolar ions optimized for finest particles, and a corona discharge region optimized for largest particles. This segmentation allows each charging mechanism to operate in its optimal performance range without interfering with the other

Inventive Principle:
Principle #1Segmentation

4Productivity

If simultaneous collection of all particles is attempted, then total collection efficiency is improved, but selective analysis capability deteriorates

Engineering Contradiction:
Improvetotal particle collectionVSAvoidparticle size distribution information
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The collection system segments particles into different size categories by directing them to different collection substrates based on their charging characteristics. This segmentation preserves particle size distribution information while maintaining high overall collection efficiency, as each substrate collects a specific size range that can be analyzed separately

Inventive Principle:
Principle #1Segmentation

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

Effectively separates and collects nanoparticles and micron-sized particles, allowing for their distinct analysis and reducing contamination by enabling the separation of fine particles while allowing coarse particles to pass, enhancing the detection of radioactive aerosols and recovery of strategic materials.

Implementation Method 1

charge of the finest particles, downstream of the inlet orifice, by diffusion of unipolar ions in a space between an electrode under the form of a grid surrounding an electrode in the form of a wire

Methodology Applied
Scientific EffectCorona discharge: Corona Discharge

Implementation Method 2

charge of the finest particles, downstream of the inlet orifice, by diffusion of unipolar ions

Methodology Applied
Scientific EffectIon diffusion: Diffusion

Implementation Method 3

generation of an electric field without corona effect in the space between an electrode and a second conductive portion of inner wall of the duct, in order to collect by deposition on a first collection substrate (Zn) of the finest particles charged by the diffusion charger

Methodology Applied
Scientific EffectElectrostatic deposition: Electrostatic Deposition

Implementation Method 4

generation of an electric field with corona effect in the space between the wire or the tip an electrode and a third conductive portion of the inner wall of the conduit, in order to collect by deposition on a second collection substrate (Zm) distinct from the first collection substrate, the largest particles, not collected by the diffusion charger

Methodology Applied
Scientific EffectCorona discharge: Corona Discharge

Data Source

PatentEP3328549B1Method for the selective purification of aerosols
Publication Date: 2019.09.25 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3328549B1 patent drawingFigure 1A~2
  • EP3328549B1 patent drawingFigure 3

AI summary

The invention relates to a method for the selective purification of aerosols. The invention consists in electrostatically collecting all of the particles present in an aerosol, but with separation of the mechanisms on one hand for charging particles by unipolar ion diffusion in order to charge and then collect the finest particles, and on the other hand for charging particles by means of Corona discharge in order to charge and then collect the largest particles on a substrate different from the substrate for collecting the finest particles.