A standard rotary cone vacuum dryer (RCVD) is a conically shaped vacuum vessel rotating slowly (1–10 RPM) about its own axis under jacket heating (30–150°C) and vacuum (−0.85 to −0.98 bar) the tumbling rotation continuously exposes fresh product surface to the heated cone wall without any internal agitator, providing gentle drying of free-flowing granules, crystalline APIs, and bulk powder with minimal attrition. Processing 50–15,000 L in 2–10-hour cycles, it achieves LOD below 0.5% w/w with solvent recovery above 98%.
Wet product is charged into the rotating conical vessel through the top inlet; the vessel is sealed, vacuum applied, and the cone rotates at 1–10 RPM. Conical geometry causes product to cascade continuously from the cone apex toward the wider end and back each rotation provides 360° of product-to-heated-wall contact without dead zones. Steam or hot water jacket (30–150°C) heats the cone wall conductively; evaporated solvent and moisture exit through a central hollow shaft connected to the vacuum system and condenser. At drying endpoint, the cone inverts and product discharges through a bottom valve by gravity achieving >99% recovery.
Challenges
Dead Zone Formation at Cone Apex in Dense or Sticky Products
Dense material packs at the narrow apex and does not participate in tumbling uneven LOD.
Vacuum Seal at Rotating Cone Axis (Hollow Shaft at Both Ends)
Continuous rotation at −0.9 bar differential stresses rotary seals at both shaft ends.
Non-Uniform Drying at Low Fill Level (<30% of Cone Volume)
At low fill, product occupies only the apex insufficient contact with full heated wall area.
Scale-Up of Cone Rotation Speed (Critical Froude Number Varies with Diameter)
Tumbling dynamics change with cone diameter rotation speed cannot be linearly transferred.
CIP of Conical Interior Including Apex and Hollow Shaft Connection
Conical apex and rotary shaft inlet create CIP shadow zones not reached by standard spray ball.
Solutions
- Raised Apex Insert (Teflon or SS 316L Plug, 15% Cone Height): Removable apex insert converts dead apex to a flat base eliminates static material zone.
- Double Carbon-Graphite Rotary Seal on Hollow Drive Shaft (Rated −0.98 bar, 150°C): Premium graphite seal rated for simultaneous vacuum and elevated temperature 15,000-hour life.
- Minimum Fill Interlock (30% of Cone Gross Volume) + Baffles on Cone Interior: Interlock prevents start below minimum fill; baffles lift material from apex to mid-cone.
- Froude Number Fr = n²D/g = Constant Scale-Up (Adjustable VFD): Maintain constant Fr = 0.02–0.06 across all sizes VFD adjusts RPM per cone diameter.
- Retractable Rotating CIP Spray Head on Hollow Shaft + Apex Flush Nozzle: Spray head advances along hollow shaft during CIP; dedicated apex nozzle clears cone tip.
Applications
- Pharmaceutical: API granule vacuum drying, crystalline intermediate final drying, excipient drying gentle, no attrition.
- Chemical: Fine chemical crystal drying, specialty powder bulk drying with full solvent recovery.
- Nutraceuticals: Free-flowing botanical powder drying, vitamin crystal drying heat-sensitive at moderate vacuum.
- Food & Beverage: Free-flowing food granule and ingredient powder drying at reduced temperature.
- Agrochemical: Active ingredient crystal and granule drying high solvent recovery required.
Models & Capacities
| Type 2A Standard Rotary Cone Vacuum Dryer: Models & Capacities (* At jacket surface temperature 50°C) | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Model | Scale | Working Vol. [L] | Gross Vol. [L] | Batch Size [kg] | Cone Ø (max) [mm] | Cone Angle [°] | Rotation Speed [RPM] | Motor [kW] | Jacket Temp [°C] | Vacuum [bar abs.] | Max Evap. Water* [kg/h] |  |  |  |  |
| RCVD-050 | Lab | 35 | 50 | 10–25 | Ø550 | 30 | 1–10 VFD | 0.55 | 30–150 | 0.02–0.15 | 1 |  |  |  |  |
| RCVD-100 | Lab/Pilot | 70 | 100 | 20–50 | Ø700 | 30 | 1–10 VFD | 0.75 | 30–150 | 0.02–0.15 | 2 |  |  |  |  |
| RCVD-250 | Pilot | 175 | 250 | 50–125 | Ø950 | 30 | 1–10 VFD | 1.1 | 30–150 | 0.02–0.15 | 5 |  |  |  |  |
| RCVD-500 | Pilot/Prod | 350 | 500 | 100–250 | Ø1,200 | 30 | 1–8 VFD | 1.5 | 30–150 | 0.02–0.15 | 8 |  |  |  |  |
| RCVD-1000 | Production | 700 | 1,000 | 200–500 | Ø1,500 | 30 | 1–8 VFD | 2.2 | 30–150 | 0.02–0.15 | 15 |  |  |  |  |
| RCVD-2000 | Production | 1,400 | 2,000 | 400–1,000 | Ø1,900 | 30 | 1–8 VFD | 3.0 | 30–150 | 0.02–0.15 | 26 |  |  |  |  |
| RCVD-3000 | Production | 2,100 | 3,000 | 600–1,500 | Ø2,200 | 30 | 1–6 VFD | 4.0 | 30–150 | 0.02–0.15 | 38 |  |  |  |  |
| RCVD-5000 | Large Prod | 3,500 | 5,000 | 1,000–2,500 | Ø2,700 | 30 | 1–5 VFD | 5.5 | 30–150 | 0.02–0.15 | 58 |  |  |  |  |
| RCVD-8000 | Large Prod | 5,600 | 8,000 | 1,600–4,000 | Ø3,200 | 30 | 1–4 VFD | 7.5 | 30–150 | 0.02–0.15 | 88 |  |  |  |  |
| RCVD-10000 | Large Prod | 7,000 | 10,000 | 2,000–5,000 | Ø3,600 | 30 | 1–4 VFD | 11 | 30–150 | 0.02–0.15 | 110 |  |  |  |  |
| RCVD-15000 | Large Prod | 10,500 | 15,000 | 3,000–7,500 | Ø4,200 | 30 | 1–3 VFD | 15 | 30–150 | 0.02–0.15 | 160 |  |  |  |  |