Particle Size Distribution Measurement via Parallel Precipitation
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Solution Overview
Problem
Existing devices for characterizing the size distribution of electrically-charged airborne particles struggle to provide accurate results under transient conditions, as they require successive application of electric field strengths and signal averaging, leading to inaccurate measurements when particle concentration and size distribution change during measurement.
Innovation Solution
The device uses simultaneously-generated output signals from multiple particle precipitation units to characterize the size distribution of electrically-charged airborne particles, allowing for simultaneous data averaging and improved accuracy even under transient conditions, by differentially precipitating particles based on size limits and using a diffusion charging unit for controlled particle charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If successive application of electric field strengths is used to characterize particle size distribution, then measurement precision is improved through signal averaging, but measurement reliability deteriorates under transient conditions where particle concentration changes during measurement
Solution Approach 1:
The device divides the particle precipitation process into multiple parallel channels, each with its own precipitation unit operating at different electric field strengths. This segmentation allows simultaneous measurement of different particle size fractions without sequential switching, resolving the contradiction between precision (through parallel measurements) and reliability (under transient conditions).
Solution Approach 2:
The patent implements continuous simultaneous measurement across multiple precipitation units operating in parallel, eliminating the intermittent nature of sequential measurements. This continuity ensures that particle concentration and size distribution are captured at a single instant, maintaining reliability under transient conditions while achieving precision through multiple concurrent measurements.
2Measurement precision
If signal averaging is performed during measurement, then measurement precision is improved, but measurement time increases making the device unsuitable for transient conditions
Solution Approach 1:
The measurement process is segmented into multiple parallel precipitation channels that simultaneously capture different particle size fractions. This segmentation eliminates the need for time-consuming sequential measurements and signal averaging over extended periods, as all necessary data is collected concurrently in a single measurement cycle.
Solution Approach 2:
The device performs excessive action by simultaneously measuring multiple particle size fractions in parallel rather than sequentially averaging signals. This approach achieves precision through redundant simultaneous measurements rather than through time-consuming signal averaging, significantly reducing measurement time while maintaining accuracy.
3Measurement precision
If multiple measurement signals are collected serially to determine total particle number concentration and average diameter, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The device segments the measurement function into multiple independent precipitation units operating in parallel, each contributing to the determination of particle concentration and size distribution. This segmentation achieves precision through diverse measurement signals while maintaining relatively simple individual unit designs, avoiding the complexity of a single complex sequential measurement system.
Solution Approach 2:
Each precipitation unit is designed with universal functionality to handle different particle size fractions through adjustable electric field strengths. This multi-functionality allows the same basic unit design to serve multiple measurement purposes simultaneously, reducing overall device complexity compared to requiring specialized sequential measurement components.
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
This approach enables reliable characterization of particle size distribution and concentration under both stationary and transient conditions, providing accurate and detailed information about airborne particles, including their number concentration and average diameter, even in dynamic environments.
Implementation Method 1
The airborne particles are charged in a particle charging unit arranged upstream from the first particle precipitation unit
Implementation Method 2
a first particle precipitation unit arranged to generate a first output signal which is a function of a length concentration of the electrically-charged airborne particles which have been precipitated in the first particle precipitation unit
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The invention relates to a device that can reliably characterize a size distribution of electrically-charged airborne particles in an air flow under both stationary conditions and transient conditions. The device comprises a particle charging unit, a first particle precipitation unit located downstream of theparticle charging unit, a second particle precipitation unit located downstream of thefirst particle precipitation unit, and a data evaluation unit. The first particle precipitation unitis arranged to partiallyreduce the concentration of electrically-charged airborne particles having a size larger than a first particle size limit, and to generate a first output signal corresponding to the precipitation of electrically-charged airborne particles inside the first particle precipitation unit. The second particle precipitation unit is arranged to precipitate substantially all entering electrically-charged airborne particles, and to generate a second output signal corresponding to the precipitation of electrically-charged airborne particles inside the second particle precipitation unit. The data evaluation unit is arranged to calculate, based on the output signals of the particle precipitation units, a particle number concentration and an average diameter of airborne particles larger than the lower particle size limit. The device enables the simultaneous generation and recording of output signals, and consequently an immediate determination of the particle number concentration and the average particle diameter at any instant.