Ultrasonic Probe Voltage Control for Particle Size Measurement
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Solution Overview
Problem
Laser diffraction methods for particle size measurement in the pharmaceutical industry face challenges with unexplained variations in precision due to issues like agglomeration and variability in ultrasonic probe performance, leading to inconsistent results across different machines and batches, which affects reproducibility and quality control.
Innovation Solution
Measuring the actual voltage produced by ultrasonic probes and adjusting the power setting to maintain a validated voltage level, ensuring consistent sonication performance and compensating for wear and corrosion, thereby improving the reproducibility of particle size measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic probes are used for de-agglomerating particles in laser diffraction measurement, then particle size measurement precision is improved, but measurement precision deteriorates due to unexplained variations and probe wear over time
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual voltage produced by the ultrasonic probe and using this measurement to adjust the power setting. A voltmeter is connected to monitor the probe voltage, and the power controller is adjusted based on this feedback to maintain the voltage within a validated range, ensuring consistent de-agglomeration performance across different probes and over time.
Solution Approach 2:
The patent changes the operational parameter from a fixed power percentage setting to a voltage-based control system. By measuring and controlling the actual voltage output of the ultrasonic probe rather than relying on a percentage power setting, the system compensates for probe wear and manufacturing variations, maintaining reliable and reproducible particle size measurements.
2Ease of operation
If fixed power percentage settings are used on ultrasonic probes, then operation is simplified, but measurement precision deteriorates due to probe wear and manufacturing variations
Solution Approach 1:
The system maintains ease of operation by providing a clear target voltage range and using a voltmeter to give immediate feedback on the actual probe output. The operator simply adjusts the power controller until the voltmeter reading falls within the validated range, combining simplicity with precision without requiring complex procedures.
Solution Approach 2:
The system enables self-service operation by allowing the operator to independently verify and adjust the probe voltage using the connected voltmeter. The operator can validate the probe performance and make necessary adjustments without requiring intervention from specialized personnel or complex calibration procedures.
3Device complexity
If ultrasonic probes operate without voltage monitoring, then device complexity is reduced, but reliability deteriorates due to inability to compensate for wear and corrosion
Solution Approach 1:
The patent introduces a straightforward voltage monitoring system using a voltmeter connected to the ultrasonic probe. This simple feedback mechanism provides real-time information about probe performance, enabling the operator to detect and compensate for wear and corrosion by adjusting the power setting to maintain voltage within the validated range.
Solution Approach 2:
The voltmeter serves as an intermediary device that bridges the gap between the ultrasonic probe and the power controller. It provides objective measurement of probe performance, enabling informed adjustment of the power setting to compensate for probe degradation without requiring complex monitoring systems.
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 reduces deviations in particle size determinations, enhances the precision of laser diffraction analysis, and extends the life of ultrasonic probes, achieving a three- to four-fold improvement in reproducibility and consistency across different machines and laboratories.
Implementation Method 1
sonicating the product of interest at a given power reading on the power controller
Implementation Method 2
Laser diffraction is a well-known technique for measuring sizes of particles in a dry powder state or suspended in a liquid suspension. A laser light is directed through the powder or suspension containing the particles to be measured. The particles cause the light to be diffracted
Data Source
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AI summary
A method and an apparatus to improve the precision and reproducibility of particle size analysis by laser diffraction is presented. Powder particles are typically prepared for laser diffraction testing using an ultra-sound bath which will disperse particle agglomerates and allow a precise measurement. However, the precision and reproducibility of agglomerate dispersion is affected by ultra-sound probe wear, corrosion and age. Differences in sonication performance can be compensated by voltage adjustments to the ultra-sound probe, leading to substantial improvements in the precision and reproducibility of particle size determination.