Microtrac S3500, Operation And Maintenance Manual, Page: 23 / 38

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9/03 Microtrac S3500 Particle Size Analyzer Operation and Maintenance 17
3. Operation
3.1 General
A complete Microtrac Model S3500 Particle Size Analyzer system consists of a wet sample recirculator
and/or a dry sample delivery device, the S3500 analyzer and a computer that is running the Microtrac
application software.
The S3500 measures light scattered from particles in a laser beam. The amount and direction of light
scattered by the particles, measured by optical detector arrays, is analyzed to determine the particle size
distribution.
Laser 1
Forward
Detector
High Angle
Detector
Laser 2
Laser 3
Sample
Cell
Figure 3-1
Microtrac Tri-Laser
Laser Diffraction Particle Size Measurement
3.2 Sample Delivery
The S3500 can measure size distributions of particles in dry form or suspended in a liquid. A variety of
sample delivery devices are available from Microtrac to fit the specific needs of your materials, application
environment and budget. Please refer to the manual(s) for the device(s) that accompany your system.
It is important to understand that “sample” means a small amount of material that is representative of a
larger batch. Materials with broader size distributions will require a larger amount per sample to provide a
statistically valid measurement. In contrast, narrower distributions of the same median size can be
represented by smaller amounts.
If you have questions regarding proper sample volume for your material, or if your sample delivery
requirements change, please contact Microtrac Technical Support.