Dynamic Filter Selection for Particle Size Distribution Measurement
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Solution Overview
Problem
Dynamic light scattering type particle size distribution measuring apparatuses face challenges in accurately measuring samples with changing particle size and concentration over time, leading to varying scattered light intensities that can result in reduced measurement accuracy due to photodetector saturation or low signal-to-noise ratios.
Innovation Solution
A particle size distribution measuring apparatus with a flow cell, light source, photodetector, and a changeable filter member that adjusts attenuation levels to maintain optimal photodetector sensitivity by selecting the appropriate filter member for each measurement, allowing for continuous measurement and accurate calculation of particle size distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a particle size distribution measuring apparatus uses a fixed photodetector bandwidth setting, then the device complexity is reduced, but the measurement precision deteriorates when scattered light intensity varies significantly across multiple measurement times
Solution Approach 1:
The patent implements a dynamic filter member selection mechanism that automatically changes the attenuation level based on the measured scattered light intensity. The system transitions from a static fixed-bandwidth approach to a dynamic adaptive bandwidth selection, where the filter member with appropriate attenuation level is selected for each measurement time to optimize the signal-to-noise ratio and prevent photodetector saturation.
Solution Approach 2:
The system changes the attenuation parameter of the optical filter based on the scattered light intensity conditions. By selecting different filter members with different attenuation levels (e.g., 0.5, 2, 10, 50 times attenuation), the system adapts the optical parameters to match the measurement conditions, thereby maintaining optimal measurement precision across varying particle concentrations and scattered light intensities.
2Productivity
If the apparatus measures particle size distribution at multiple time points without adjusting attenuation, then the productivity is improved, but the measurement precision deteriorates due to photodetector saturation or low signal-to-noise ratio
Solution Approach 1:
The system employs a feedback mechanism where the scattered light intensity measured at each time point is used to determine the appropriate filter member for the next measurement. The measurement results feed back into the filter selection process, creating a closed-loop control system that automatically adjusts the attenuation level to maintain optimal signal-to-noise ratio throughout the continuous measurement process.
Solution Approach 2:
Before performing the actual particle size distribution measurement at each time point, the system preliminarily determines the appropriate filter member based on the scattered light intensity conditions. This preliminary action of selecting the correct attenuation level ensures that the subsequent measurement is performed under optimal conditions, preventing both saturation and low signal-to-noise ratio issues.
3Adaptability or versatility
If the apparatus uses a single filter member for all measurements, then the device complexity is reduced, but the adaptability deteriorates when dealing with samples having varying particle size and concentration
Solution Approach 1:
The system transitions from a static single-filter configuration to a dynamic multi-filter selection system. By implementing a mechanism that can switch between multiple filter members with different attenuation levels, the system gains the adaptability to handle a wide range of measurement conditions, from low to high scattered light intensities, while maintaining a relatively simple overall structure through automated selection.
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 configuration ensures high measurement accuracy by maintaining optimal photodetector sensitivity and bandwidth, improving the accuracy of combined particle size distribution measurements by adjusting the filter member's attenuation level at each measurement time.
Implementation Method 1
a fluctuation in the intensity of scattered light obtained when radiating measurement light to a particle group dispersed in a medium
Implementation Method 2
a filter member that is arranged in a predetermined position in a light path of the measurement light from the light source to the cell or a light path of the scattered light from the cell to the photodetector and attenuates the measurement light or the scattered light
Data Source
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AI summary
Provided is a dynamic light scattering type particle size distribution measuring apparatus 100 capable of accurately measure the particle sizes of a sample obtained from slurry or the like. The dynamic light scattering type particle size distribution measuring apparatus 100 is configured to include: a filter member 6 that is interposed between any adjacent two of a light source 4, a cell 2, and a photodetector 5 and attenuates light passing therethrough; and an information processing device 8 that measures a particle size distribution multiple times with time and combines particle size distributions obtained at respective times of measurement to thereby calculate the particle size distribution of the whole of portions of the sample introduced at the respective times of measurement. In addition, the filter member 6 is also configured to be changeable to one having a different attenuation level at every time of measurement.