Wet product is charged into the jacketed vessel; vacuum is applied and the agitator starts at 3–30 RPM. The jacket (40–150°C) heats the vessel wall; the agitator continuously turns the product, renewing heated-wall contact surface and drastically increasing effective heat transfer area vs. static tray dryers. Evaporated moisture and solvent exit through vacuum to a condenser. The agitator also breaks dried crust at the wall maintaining free-flowing product bed and preventing hotspot formation.
Challenges
Product Attrition from Agitator Shear on Fragile Granules
Rotating blades fracture fragile granule or crystal structures during drying.
Agitator Shaft Seal Integrity at Vacuum and Elevated Temperature
Shaft seal under −0.9 bar and 150°C simultaneously stresses seal face materials.
Product Compaction Around Agitator Shaft at Drying Endpoint
As product dries it compacts around the shaft increases torque and risks blockage.
Scale-Up Heat Transfer Estimation
U value varies with viscosity, fill level, and agitator speed scale-up requires pilot data.
Cleaning Validation of Agitator Blades and Shaft Crevices
Complex blade attachment points create CIP shadow zones.
Solutions
- Low-Shear Helical or Paddle Agitator for Fragile Granules (3–8 RPM): Gentle helical sweep at low tip speed (<0.5 m/s) moves product without fracturing structure.
- Double Mechanical Seal with Barrier Fluid (Vacuum and 150°C Rated): Bidirectional pressure seal rated −0.9 bar to +2 bar barrier fluid maintains face temperature.
- VFD Agitator with Torque Overload Protection and Auto-Reverse: PLC torque monitoring triggers auto-reverse then reduces speed at endpoint compaction.
- Pilot-Scale (50 L) AVD Trial for U-Value and Cycle Time: Pilot drying generates U value and cycle time data for production-scale design.
- Electropolished Agitator (Ra <0.4 µm) + CIP Spray Nozzle at Shaft Root: Ultra-smooth surfaces minimise adhesion; dedicated nozzle at shaft base clears root crevice.
Applications
- Pharmaceutical: Wet granule vacuum drying, API paste drying, wet cake drying after ANFD faster cycle vs. VTD.
- Chemical: Viscous polymer, resin, and adhesive solvent drying high fill volumes with agitation prevent crust.
- Food & Beverage: Viscous food paste drying, instant beverage concentrate, hygroscopic ingredient drying.
- Nutraceuticals: High-value botanical paste drying, protein concentrate drying, viscous supplement intermediate.
- Cosmetics: Wax, cream paste, and active ingredient concentrate drying temperature-sensitive formulations.
Models & Capacities
| Type 1C Agitated Vacuum Dryer (AVD): Models & Capacities (* At jacket surface temperature 60°C) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Model | Scale | Working Vol. [L] | Batch Size [kg] | Agitator Type | Jacket Temp [°C] | Vacuum [bar abs.] | Max Evap. Water* [kg/h] | Max Evap. Ethanol* [kg/h] | Motor [kW] | Vessel Ø×H [mm] |  |
| AVD-020-P | Lab | 20 | 5–14 | Paddle | 40–150 | 0.02–0.15 | 1 | 3 | 0.55 | Ø400×250 |  |
| AVD-050-P | Lab/Pilot | 50 | 15–35 | Paddle | 40–150 | 0.02–0.15 | 2 | 5 | 0.75 | Ø550×320 |  |
| AVD-100-P | Pilot | 100 | 30–70 | Paddle | 40–150 | 0.02–0.15 | 4 | 10 | 1.5 | Ø700×400 |  |
| AVD-100-PL | Pilot | 100 | 30–70 | Plough | 40–150 | 0.02–0.15 | 4 | 10 | 2.2 | Ø700×400 |  |
| AVD-250-P | Production | 250 | 75–175 | Paddle | 40–150 | 0.02–0.15 | 8 | 20 | 3.0 | Ø950×560 |  |
| AVD-500-H | Production | 500 | 150–350 | Helical | 40–150 | 0.02–0.15 | 15 | 38 | 4.0 | Ø1,200×700 |  |
| AVD-1000-H | Production | 1,000 | 300–700 | Helical | 40–150 | 0.02–0.15 | 25 | 65 | 5.5 | Ø1,600×850 |  |
| AVD-2000-PL | Production | 2,000 | 600–1,400 | Plough | 40–150 | 0.02–0.15 | 50 | 125 | 11 | Ø2,000×1,000 |  |
| AVD-5000-H | Large Prod | 5,000 | 1,500–3,500 | Helical | 40–150 | 0.02–0.15 | 100 | 250 | 18.5 | Ø2,800×1,300 |  |
| AVD-10000-PL | Large Prod | 10,000 | 3,000–7,000 | Plough | 40–150 | 0.02–0.15 | 200 | 500 | 37 | Ø3,800×1,700 |  |