When it comes to measuring the particle size of powders, two primary methods stand out: Fisher Sub-Sieve Sizer (FSSS) and Laser Particle Size Analyzer (LPSA). While both techniques provide valuable insights into particle size distribution, they differ significantly in their principles of operation, measurement range, and suitability for various materials.

Understanding the Differences

Measurement Principle:

• FSSS: Employs air permeability to determine particle size, measuring the resistance of air flow through a packed bed of powder.
• LPSA: Utilizes laser diffraction to analyze the scattering pattern of light as it passes through a dispersed sample.

Measurement Range:

• FSSS: Typically measures particles in the 0.2-50 micron range.
• LPSA: Covers a broader range, from 0.03 to 1000 microns.

Particle Size Distribution:

• FSSS: Provides average particle size, specific surface area, and porosity.
• LPSA: Offers a detailed particle size distribution, including median size, mode size, and percentile sizes.

Suitability for Different Materials:

• FSSS: Well-suited for a wide range of materials, including hard alloys, magnetic powders, and pharmaceutical powders, even those difficult to disperse.
• LPSA: May have limitations with materials that are difficult to disperse or have non-spherical shapes.

Why Choose FSSS?

• Lower Cost: FSSS instruments are generally more affordable than LPSA systems.
• Robustness: Less susceptible to external factors like temperature and humidity fluctuations.
• Ease of Use: Simple operation and minimal maintenance requirements.
• Effective for Sub-Micron Particles: FSSS excels in measuring particles in the sub-micron range.

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