Fine Particle Software - Experts in Particle Technology

Grade Efficiency Evaluation

This program allows the user to evaluate grade efficiency curves for different types of separators where particulates are separated from gases or from liquids. The particulates may be solid particles or liquid droplets and the concept is therefore equally applicable to any of the following cases:

solid-solid separation (classification of solids in liquid or gaseous media)
solid-liquid separation (sedimentation, centrifuges, hydrocyclones, deep bed filters, cartridge filters, rating of filter media etc.)
solid-gas separation (gas cleaning)
liquid-liquid separation (immiscible liquids)
liquid-gas separation (LiG separators)

Grade efficiency evaluation

There are altogether four different options of the evaluation depending on the particle size distribution data available: the first three are based on the measurements of different combinations of two out of the three material streams (feed, overflow and underflow) plus the total efficiency (recovery), and the fourth option uses particle size distributions in all three material streams. All four options require data in the cumulative form (cumulative percentages oversize or undersize) and the quantity by which these are measured must be consistent with that of the total efficiency.

The evaluation is based on the well-tried and tested method developed by Dr. L. Svarovsky by which two particle size distributions are plotted against each other and tangents taken at different points along the resulting curve. A second-order polynomial is in turn fitted to each three adjacent points and the slope is taken at the middle point. Full high resolution plots are made to allow the user to see the intermediate plots as well as the final grade efficiency curve. The user also has the option to adjust the data if any point is clearly out of line with the rest and the effect on the results can be observed.

Final plot of grade efficiency