Apparatus for manufacturing readily soluble granular substances from powdered materials

An apparatus for manufacturing readily soluble granular substances from powdered materials such as, for example, coffee, milk and the like. The apparatus has a vertical outer hollow cylindrical body for allowing quantities of powdered material from a distributor to fall by gravity therethrough, and a vertical inner hollow cylindrical body of different length and diameter inside the outer cylindrical body. The two concentric cylindrical bodies partly overlap each other and define a circumferential gap therebetween extending along the overlapping portion. A pneumatic air supply is provided on the outer cylindrical body for introducing compressed air into the outer body and producing a whirling air stream in the gap so that the powdered material carried by the whirling air stream forms a thin, ring-like continuous curtain. Also, first and second steam supply means are provided in the inner body and at the bottom of outer body for blowing steam against the curtain-shaped powdered material in the gap from the inside and outside.