In this study, prediction of transition from fixed bed to spouting bed are carried out and different spouting regimes are characterized by analysis of pressure fluctuation signals. Pressure signals are measured in three different constructions of spouted bed apparatuses, operated under ambient conditions and under different spouting regimes. The presented spouted beds are developed for handling of non-spherical particles and poly dispersed and finely dispersed systems. Several flow regimes are found to exist as: fixed bed, channel formation, bubbling formation, stable spouting and slugging bed regimes. Different methods, based on time domain analysis, frequency domain analysis and phase space analysis have been applied to identify the flow regimes. Stable spouting regime is characterized by a low amplitude (respectively, low standard deviation) of pressure fluctuations, maximum in the dominant frequency. Time-series analysis of pressure fluctuations in spouted beds, using techniques from deterministic chaos theory, has revealed that a spouted bed is a chaotic system that can be characterized with a low-dimensional strange attractor. (c) 2006 Elsevier B.V. All rights reserved.