SPRAY DRYING MACHINE AND SPRAY DRYING METHOD USING THE SAME

PROBLEM TO BE SOLVED: To stably obtain fine dry particles by disposing two-fluid nozzles on concentric circles in the horizontal cross section of the upper part of a parallel flow type spray drying machine and radially arranging the two-fluid nozzles. SOLUTION: The two-fluid nozzles 7 are radially arranged on the concentric double circles designed in such a manner that the radius of the inner concentric circle 9 is 7/16 to 10/16 of the radius of a straight cylindrical part and that the radius of the outer concentric circle 8 is 10/16 to 14/16 of the radius of the straight cylindrical body. The two-fluid nozzles 7 thus arranged are designed in such a manner that the angle of the inner side wall of the gas passage to the center axis and the angle of the outer side wall of the gas passage to the center axis satisfy a specified relation and that the objective liquid such as a dispersion liquid of a thermoplastic resin such as a polyester, polystyrene and polyamide can be finely sprayed. Thus, production of coarse particles due to collision or coalescence among the sprayed particles can be prevented and dry particles of a minute particle size can be stably obtd.