SEARCH Articles Figures Tables Dry Compressing, Three-Stage Roots Vacuum Pump with Exhaust, Respectively Non-Return Valves between the Stages Drying three-stage dryer Freeze during primary drying stage Freeze-drying cycle process stages Plate drying stages Primary freeze-drying stage Single stage spray drying Spray Drying Process Stages Spray drying stages Temperature single-stage drying systems Three-stage spray drying system Two-stage drying