Dynamic Particle Trap Cut-Off Diameter Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing particle measurement devices that rely on electrically charging particles and measuring electrical current face challenges in accurately converting current signals into actual particle flow characteristics, such as number concentration and mass concentration, especially when the particle mean diameter changes.
Innovation Solution
The process involves dynamically adjusting the cut-off diameter of a particle trap based on the measured electrical current, using at least two different cut-off diameters - a reference cut-off diameter and a measuring cut-off diameter - to reduce measurement errors caused by changes in the count median diameter of particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed cut-off diameter is used in particle measurement, then the measurement process is simple, but the measurement precision deteriorates when particle size distribution changes
Solution Approach 1:
The patent implements dynamic adjustment of the particle trap cut-off diameter based on real-time monitoring of particle size distribution. The system continuously adapts the cut-off diameter to match the count median diameter of the measured particles, transforming a static measurement system into a dynamic one that maintains optimal measurement conditions despite changes in particle characteristics.
Solution Approach 2:
The system employs feedback control by measuring the electrical current at a reference cut-off diameter, comparing it to determine the count median diameter, and then adjusting the measuring cut-off diameter accordingly. This closed-loop feedback mechanism ensures that the measurement system automatically compensates for changes in particle size distribution, maintaining high measurement precision without manual intervention.
2Measurement precision
If the cut-off diameter is adjusted to match count median diameter, then measurement precision improves, but device complexity increases
Solution Approach 1:
The measurement system performs self-calibration by automatically determining its own operating parameters. The system uses the electrical current measurements to self-determine the count median diameter and self-adjust the measuring cut-off diameter without requiring external calibration equipment or manual intervention, thereby reducing operational complexity while maintaining high precision.
Solution Approach 2:
The system changes the operational parameter (cut-off diameter) based on measured conditions. By dynamically adjusting the cut-off diameter to match the count median diameter, the system adapts its parameters to the specific measurement conditions, improving precision while the automation of this process prevents excessive complexity increase.
3Productivity
If electrical current is measured to determine particle characteristics, then measurement speed is fast, but measurement precision deteriorates due to conversion errors
Solution Approach 1:
The system performs preliminary determination of the count median diameter using electrical current measurements at a reference cut-off diameter before conducting the actual concentration measurement. This preliminary action allows the system to pre-adjust the measuring cut-off diameter to optimal values, ensuring that the subsequent fast electrical current-based concentration measurement is performed under conditions that minimize conversion errors and maximize precision.
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 significantly improves the accuracy of both number and mass concentration measurements by maintaining a consistent correlation factor, even when the particle size distribution changes, thereby reducing the sensitivity of current-to-mass concentration conversion to median diameter variations.
Implementation Method 1
The ionizing of the clean gas may be carried out for example using a corona charger
Implementation Method 2
trapping means for trapping essentially all free ions and charged particles
Implementation Method 3
The clean gas is further ionized before and during supplying it into the inlet chamber. The ionized clean gas may be preferably fed to the ejector at a sonic or close to sonic speed
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to an apparatus (1) and process for measuring characteristics of a particle flow. The measuring is done with two different cut-off diameters of a particle trap (13) of which one cut-off diameter is adjusted based on the measured particle characteristics.