A Simple Sub-sieve sizer employing elutriation with water

Particle size determination of fine minerals and clay powders below 40 micron is required in the industry. Various types of apparatus are in vogue today for their sub-sieve sizing. Strokes law forms the basis of this determination by subjecting the sample to sedimentation
or elutriation. The medium used may be any fluid includ-
ing air or water. Some of the commonly used units for
the purpose may be named such as Andresen Pipette(1), Sedigraph(2) both working on sedimentation principle; haultain air separator(3) and Blythe water elutriator(4) both working on the principle of elutriation. Beaker decantation and Andresen Pipette are the simplest units. However, they are time consuming and require repetition
of the tests for accuracy and reliability. The other commercial units are rapid but expensive.