Abstract: The present invention discloses a method and an apparatus for drying granular materials by submitting them to dielectric heating by means of electromagnetic waves such as microwave, high frequency, etc. The granular materials to be dried are heated to the prescribed temperature with electromagnetic waves under a reduced pressure of a range not producing any glow discharge and then dried to the prescribed moisture percentage while passing through a pressure reducing process of a vacuum of higher degree. An apparatus for it is provided with a reduced pressure drying tank (1) having an electromagnetic wave generator (2), a main drying tank (30) communicated with said reduced pressure drying tank (1), and suction air sources (20), (20') which are provided respectively in the reduced pressure drying tank (1) and the main drying tank (30).

Abstract: The invention is directed to an apparatus for drying powdered or granular materials comprises a drying tank (1) including a transversely extending drying room (7) adapted to be applied with heating by microwaves, at least one partition (20) defining more than two drying zones in the drying room (7) of the drying tank (1), a rotary shaft (12) disposed in the drying tank (1) in its longitudinal direction to extend through the drying room (7) in a manner of being freely rotatable and agitating blades (30a), (30b) . . . provided on the rotary shaft correspondingly to each drying zone, microwave application units (40) provided for each drying zone, and temperature sensors (50) for each drying zone and corresponding temperature adjusters (51) connected to the respective temperature sensors (50).