A rolling-screw system was used as a drive for a vibratory dryer between a tank dryer and a fluidized bed dryer to change the drying process from a periodic to a continuous one. The air flow resistance through urea pellet layer in a periodical screw drier was studied as a function of the air flow rate to det. the circuital speed of the urea layer necessary to mixing the deposit. The circuital speed of the urea deposit submitted to vibrations was higher than that of stationary deposit and depended on the deposit mass. The unitary pressure decrease along the urea layer depended on the air flow speed through the deposit and was accurately described by the Ergun equation. The resistance coeff. of the air flowing through the urea layer inside the vibratory dryer was lower than that of flowing through the stationary deposit. The decrease in unitary resistance and in the resistance coeff. of the air flowing through the vibrating deposit resulted from the vibrations dependent deposit loosening.