009-iso compliance of the dry jet dispersion technology
DESCRIPTION
009-IsO Compliance of the Dry Jet Dispersion TechnologyTRANSCRIPT
ISO Compliance of the Dry Jet Dispersion Technology
CILAS Dry mode measurements use a new dispersion technology called
Dry Jet Dispersion (DJD). This technology provides you with:
- high dispersion efficiency,
- great reproducibility.
The DJD de-agglomeration concept guarantees particles will not break
apart and the results will be traceable.
Figure 2 : Visualisation of dry particle flow
Figure 1 : Software Simulation of the velocity distribution in the mixing chamber
The ISO 13320 standard explains how to calibrate and verify a particle size analyzer using Certified
Reference Materials ‘CRMs’. CRMs are measured using 5 primary methods to be sure of the powder size.
The results are traceable to major international standards (NIST).
Validation should be done using spherical CRMs such as glass beads and using the Mie theory.
Introduction
The standard requires that the manufacturer calibrate the instrument using Certified Reference Materials
(CRMs) of a known size distribution. The user must also verify operation of the instrument, both
repeatability and accuracy, at regular time intervals using CRMs. The main requirements of the standard
are presented in table 1.
Table 1: Summary of the main requirements of the ISO 13320 standard.
Mean value over 3 independent measurements
Maximum deviation from the certified range:< 3% for X50
< 5%* for X10 & X90
Accuracy (6.5 in the standard)
The measurement is done on at least 5 different samples
from the same batch
Coefficient of variation:< 3% for X50
< 5%* for X10 & X90
Repeatability(6.4 in the standard)
Test MethodTarget valuesRequirement
The ISO 13320 Standard
*below 10µm, these values should be doubled
009
Certified Reference Materials (CRMs) (figure 3) are made of spherical
particles and the size distribution of these particles must be established
by using an absolute method.
There are 5 absolute methods for size characterization: Electroformed
Sieve, Gravitational Sedimentation, Centrifugal Sedimentation, Optical
Microscopy and Electrical Sensing Zone. The size distribution ratio of a
CRM is 1:10 (for example, a size distribution from 10 to 100 µms).
Several companies distribute CRMs : NIST and Whitehouse Scientific.
Whitehouse Scientific manufactures a single-shot glass microsphere
covering the complete range of measurement from 0.1 to 2,500 µm.
Figure 3 : SEM Picture of Certified Glass Beads
Figure 4 : Vials from CILAS calibration kit Calibration and verification of a CILAS particle size
analyzer in wet and/or dry modes are similar. Powders
traceable to international standard, called CILAS
Secondary Reference, are used: CSR1 and CSR2. The validation is performed using glass bead CRM
from Whitehouse Scientific Ltd (figure 4).
Whitehouse Glass Bead Measurements
The reproducibility of the measurements made using 10-100µm glass beads with Dry Jet Dispersion is better than 1% (see figure 5).
The ISO 13320 standard requires that reproducibility must be better
than 3% with respect to the median value.
All CILAS particle size analyzers are fully compliant with the 13320
standard.
The powders needed for calibration or validation are
available in a hard-sided case which contains single
shot vials used to perform the measurements.
The vials of CSR1, CSR2 and the Whitehouse glass
beads are traceable to international standards.
CILAS allows the user to self-perform the calibration
and verification with the powders provided in the calibration kit.
Available CRM
Figure 5 : Measurement of the 10-100µm CRM with a CILAS 1064 Particle Size Analyser
Dry Jet Dispersion Calibration complies with the ISO 13320
standard. The goal of the calibration is to correct any possible
hardware deviations during the product’s lifetime.
All of the hardware components used in the acquisition system
(laser, lens, sample cell, electronic components, photodiodes)
have imperfections and manufacturing tolerances. The sum of
these tolerances can cause deviations in the reproducibility and the accuracy of the results.
The system calibration takes into account all these deviations
and enables you to adjust the response of the instrument in
comparison with expected values from certified materials.
Dry Mode Calibration and Verification
Figure 6 : Reproducibility (5 measurements) of 10-100µm glass beads from Whitehouse
The same ISO Calibration method is used for both wet and dry mode. This results in an excellent
correlation between the two different modes with respect to the demands of the ISO standard (figure 6
and 7).
For the same instrument, CILAS can guarantee the following results:
Figure 7 : Dry and wet mode correlation for CSR2 powder
Dry and Wet Mode Correlation
- Accuracy: <3% - Reproducibility: less than 1% on D50
CILAS is the only particle size analyzer manufacturer who calibrates the optical
bench and the dispersing system at the same time. Calibrating both systems at the
same time allows the user to eliminate measurement errors due to the powder
dispersion system.
Our instrument with DJD technology is completely ISO compliant.The major advantage of CILAS technology is that both modes of dispersion
are calibrated and validated using the same procedure. This allows the user
good correlation between the two modes and a greater accuracy.
Conclusion
[1] The Development of New Reference Standards For Particle Size Instrument Calibration Rideal, Dodds, Lechonski, Loyd, Mercus, World Congress on Particle Technology 3 (IchemE), 1998, Brighton, England
[2] International Standard , ISO 13320-1, “Particle Size Analysis-Laser Diffraction Methods”, General Principles
Bibliography
Measurement of the CRM with a CILAS 1064
Figure 8 : Reference Curve for 10-100 µm CRM (from Whitehouse Sc.)
The CILAS 1064L instrument was used to measure the Whitehouse Scientific Certified Reference Material. Data collected using the CILAS 1064L showed better repeatability and accuracy values than required in the ISO 13320 standard. Statistics from over 50 production instruments have shown a reproducibility of better than 1% (figure 8).
The following standards were measured:• Polydispersed standard 1-10µm• Polydispersed standard 10-100µm• Polydispersed standard 3-30µm• Polydispersed standard 50-350µm