PURPOSE: To obtain a drying tower generating no particle adhesion to the wall thereof and having a markedly reduced tower diameter, by a method wherein a high temp. air jet is issued at a high speed from a usual hot air blow-out pipe having a pressure nozzle provided to the central part thereof to be diffused into secondary air introduced from the periphery thereof and the obtained high speed jet stream is reduced at the downstream thereof.
CONSTITUTION: A hot air blow-out pipe 1 having a liquid spray nozzle 2 is provided in a drying tower 7 having a small diameter and a height changeable orifice branch 4 is provided by a support 5 at the downstream part thereof. Liquid droplets of a substance to be dried from the nozzle 2 is emitted as a high speed jet stream along with hot air from the hot air blow-out pipe 1 provided to the periphery of the nozzle 2 and diffused into a secondary air stream from a secondary air introducing part 6 provided to the periphery of the hot air blow-out pipe 1. At this time, a vortex stream due to the high speed jet stream generated directly after the hot air blow pipe 1 by the effect of the orifice branch 4 is pushed behind the stream and the distribution of pressure around the hot air blow-out pipe 1 becomes uniform. Therefore, deposition of particles to the wall surface of the drying tower 7 is hardly caused.
KUDOU TOMOAKI
FUKUSHIMA MASAYOSHI
