Powder Particle Equivalent Diameter Measurement via Dynamic Flow
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Solution Overview
Problem
Existing methods for determining the equivalent diameter of powder particles, such as the FSSS method, are time-consuming and lack precision due to their reliance on steady-state conditions and inaccurate porosity measurements, leading to a broad measurement spread and the need for lengthy measurement times.
Innovation Solution
A process that determines the equivalent diameter by recording a non-linear characteristic of pressure difference (Δp) versus volume flow rate (Q) over time, allowing for dynamic changes in both parameters, eliminating the need for steady-state conditions and improving precision through multivariate regression analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steady-state conditions are used in conventional methods (FSSS), then measurement reliability is improved, but measurement time increases significantly
Solution Approach 1:
The patent applies dynamics by transitioning from static steady-state measurements to dynamic non-steady-state measurements. The volume flow rate is varied continuously over time rather than maintained constant, allowing the system to capture particle size information during the transient phase. This dynamic approach eliminates the need to wait for steady-state conditions while maintaining measurement reliability through mathematical modeling of the transient flow characteristics.
Solution Approach 2:
The patent changes the operational parameter from constant volume flow rate to time-varying volume flow rate. By systematically varying the flow rate parameter over time and analyzing the resulting pressure differential changes, the method extracts particle size information without requiring the system to reach steady state. This parameter change enables simultaneous reduction of measurement time while maintaining reliability through controlled variation.
2Device complexity
If conventional FSSS method is used, then equipment simplicity is maintained, but measurement precision deteriorates due to broad measurement spread
Solution Approach 1:
The patent implements feedback by continuously monitoring the pressure differential across the powder sample during the varying flow rate experiment. The system uses the measured pressure changes as feedback to calculate the equivalent diameter through mathematical relationships derived from the transient flow characteristics. This feedback mechanism enables precise measurement while maintaining relatively simple equipment by utilizing the natural response of the system to flow rate variations.
Solution Approach 2:
The patent substitutes the mechanical approach of waiting for steady-state conditions with a mathematical modeling approach. Instead of relying on mechanical equilibrium to achieve precise measurements, the method uses mathematical relationships between transient flow parameters and particle size. This substitution allows for higher precision without requiring complex mechanical systems to maintain steady state, as the mathematical model processes the dynamic data to extract accurate particle size information.
3Reliability
If porosity measurement is performed separately, then measurement completeness is improved, but total measurement time increases
Solution Approach 1:
The patent merges the particle size measurement and porosity measurement into a single integrated experiment. By performing both measurements simultaneously during the transient flow rate variation, the method eliminates the need for separate measurement steps. The pressure differential data obtained during the flow rate variation contains information about both particle size and porosity, allowing both parameters to be extracted from one experiment. This merging significantly reduces total measurement time while maintaining measurement completeness.
Solution Approach 2:
The patent applies universality by designing an experiment that serves multiple measurement functions simultaneously. The single transient flow rate variation experiment provides data for both equivalent diameter calculation and porosity determination. The mathematical model processes the pressure differential and flow rate data to extract both particle size and porosity information, making the measurement system multi-functional and eliminating the need for separate dedicated measurements for each parameter.
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 measurement time while enhancing precision, achieving a narrower distribution of measured values and overcoming the limitations of conventional methods by varying the volume flow rate or pressure difference as a function of time.
Implementation Method 1
A gas flow is passed through a defined powder pellet, and the pressure difference is measured
Implementation Method 2
the pressure difference is measured (see FIG. 5a). Using the Carman-Kozeny equation (1), the equivalent diameter (D) can be derived from the ratio of pressure loss and gas flow rate
Implementation Method 3
Using the Carman-Kozeny equation (1), the equivalent diameter (D) can be derived from the ratio of pressure loss and gas flow rate
Data Source
AI summary
The present invention relates to a process for determining the equivalent diameter of particles of a powder, and a device for performing such process.