Abstract: In order to effect expansion of a shredded material, said material is impregnated with an inert organic liquid, which is subsequently vaporized. The major portion of the impregnation agent is removed by separation. In order to eliminate the residual amount of impregnation agent still contained in the material, the material is fed by conveyor belt (31) into a microwave chamber (35). The microwave chamber (35) is provided with microwave energy under continuous control conditions. The vapors are siphoned off and fed into a regenerator for recovery of the impregnation agent. Conditioned, pressurized air is directed at the material in the microwave chamber (35) through discharge nozzles (38) to cause the material to whirl up and become fluidized. The pressurized air serves as a carrier gas for the residual impregnation agent that is to be removed and may simultaneously be used for conditioning the tobacco.

Abstract: Apparatus to expand shredded material, the latter is impregnated with an inert organic liquid which is evaporated subsequently. The substantial portion of the impregnant is separated. To eliminate the residual amount of impregnate still contained in the material, the material is fed in heaps on a conveyor belt (36) to a microwave chamber (39). Upstream and downstream of the microwave chamber, one sluice each (38,40) is provided. The gates (43,44;49,51) of the sluice are synchronized with the drive of the conveyor belt (36). Microwave energy is supplied under continuous control to the microwave chamber (39). The vapors are removed by suction lines (47,55) and fed to a regenerator for recovery of the impregnant.