Particle size determination by Sieving dates back to the time of the ancient Egyptians. The continuing use and popularity of this technique can be attributed to the fundamentally simple principle, methodology, historical reference, and cost effectiveness. An analysis consists of using sieves (typically woven wire mesh), decreasing in opening size, to separate or classify a sample by particle size. A known mass of sample is added to the top sieve then dispersed through the mesh opening until a stable mass is reached on each sieve in the stack. The mass remaining on the sieve is measured and reported as a percentage of the sample mass that is larger than the verified woven wire mesh opening size. Vibration, air entrainment and flowing liquid are all dispersion methods that can be used to move the sample through the mesh.
This testing is recognized by numerous guidance agencies including the ISO, ASTM, USP, and EP. Several factors must be considered when developing a robust sieving method or performing a routine quality analysis. Sample size, sieving duration, controlled agitation parameters and end point determination are all critical method variables. PTL’s various sieving capabilities and detailed procedures, which incorporate the topics above, ensure that the best possible results are generated. For optimal quality control, PTL verifies its in-house sieves with an external vendor for compliance with the ASTM E-11 standard.
A wide variety of sample types can be analyzed for particle size classification using the sieving technique. Industries that typically use this technique include, but are not limited to, pharmaceutical, industrial, agricultural, environmental and chemical. Common applications of this analysis include quality assurance, batch testing, comparative studies, environmental studies as well as research and development.
Ideal sample amount for Standard Sieve Stack is 100 grams.
For Sonic Sifter and Air Jet testing, 10 to 20 grams is preferred.
The above sample quantities are preferred. If sample availability is further limited, please contact us to share specifics about your sample and options for suitable sample quantities.
Sieving from 45 µm and above is recommended for Standard and Sonic Sifter Sieve Stacks.
Air Jet Sieving is capable of sizing down to 20 µm if necessary but alternative particle sizing techniques are recommended below 45 µm.
Sieve results are reported as the differential weight percent retained on each sieve as well as the cumulative weight percent less than the sieve size. Specific reporting requirements are easily adjusted based on the client’s request.
• Hosokawa Micron Air Jet Sieve (MAJS) with standard 200 mm diameter, half height sieves (if multiple sieves requested, analyzed one at a time)
• VariSifter™ Sonic Separator VS1000 Sieve Stack (45 µm and above, up to 6 sieves)
• Dry Sieve Stack (up to 7 standard 8″ diameter sieves)
• Wet sieve stack (up to 7 standard 8″ diameter sieves)
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