  This paper describes application of information granulation theory, on the
analysis of hydrocyclone perforamance. In this manner, using a combining of
Self Organizing Map (SOM) and Neuro-Fuzzy Inference System (NFIS), crisp and
fuzzy granules are obtained(briefly called SONFIS). Balancing of crisp granules
and sub fuzzy granules, within non fuzzy information (initial granulation), is
rendered in an open-close iteration. Using two criteria, "simplicity of rules
"and "adaptive threoshold error level", stability of algorithm is guaranteed.
Validation of the proposed method, on the data set of the hydrocyclone is
rendered.
