Experimental investigation has shown that modified pulsations (MP) affect bed structure. This enables one to combine the profitable properties with a classical pulsed fluid bed (PFB) and of a fluid bed system. In order to classify the MP system, the gas distributor factor (Z(R)) was introduced. Experiments for various Z(R) for various bed ' structures were carried out. In the range of 0 < Z(R) < 1, two characteristic areas were found. In the first one, for 0 < Z(R) < 0.3 and H-0 = 100 mm, there is a new kind of system with oscillating particles of a solid phase and greater gas consumption when compared with the classical PFB. In the second area for gas stream distribution factor ranging from 0.3 to 1, oscillations in the bed were not observed. In this range of Z(R) intensive mixing of particles in the bed was found. The best mixing of particles in the bed was obtained for 0.3 less than or equal to Z(R) less than or equal to 0.43. This kind of system was called "a pseudo-fluid bed". The results-confirm that the new system with modified pulsation may be recommended for drying materials in constant rate period.