Vacuum Paddle Dryer
Vacuum Paddle Dryer
Mechotech engineers and manufactures the Vacuum Paddle Dryer as turnkey process equipment for pharmaceutical, nutraceutical, food, and botanical processing lines that need straightforward, single-shaft agitated drying of wet solids and pastes under vacuum. A single rotating paddle shaft inside a jacketed horizontal vessel keeps the product moving against the heated wall so it dries evenly at reduced temperature, offering a simpler, batch-oriented alternative to a dual intermeshing-paddle system for processors whose feed does not need the heaviest lump-breaking action.
The Vacuum Paddle Dryer is built in SS 316L (or a process-appropriate grade) as a horizontal, jacketed vessel with a single internal paddle shaft that rotates at low speed, continuously lifting and turning the wet solid or paste so it repeatedly contacts the heated wall rather than sitting static against it. With the vessel under vacuum, moisture or solvent evaporates at a reduced temperature and is drawn to a condenser for recovery, giving gentler, lower-shear agitation than a twin-shaft intermeshing paddle design — well suited to batch drying of feeds that need consistent mixing and even heat transfer but not the aggressive lump-breaking of stickier, harder-caking pastes. Electropolished product-contact surfaces, a fully enclosed shell, and PLC-based control of paddle speed, jacket temperature and vacuum support repeatable batch cycles, and capacity is configured to the customer's requirement from pilot-scale vessels for process trials to larger production units.
Process Flow
Technical Specifications
| Equipment Type | Vacuum Paddle Dryer — single-shaft paddle-agitated vacuum dryer |
|---|---|
| Vessel Shape | Horizontal cylindrical shell, fully jacketed |
| Construction | SS 316L (or process-appropriate alloy), electropolished product-contact surfaces |
| Agitator | Single paddle shaft, low-speed rotation |
| Heating | Jacketed shell, heated by hot water / steam / thermic fluid |
| Vacuum System | Vacuum pump with external condenser |
| Feed Type | Wet solid, granular material or moderate-consistency paste |
| Operating Mode | Batch |
| Discharge | Bottom discharge valve, paddle-assisted clearing |
| Automation | PLC-based control of paddle speed, jacket temperature and vacuum level |
| Monitoring | Jacket temperature, vacuum level, paddle torque/power draw |
| Cleaning | CIP-capable, fully enclosed shell |
| Capacity | Configured to requirement — pilot-scale vessels to larger production units |
| Utilities | Hot water / steam / thermic fluid for jacket heating, vacuum system utilities, electric power |
| Compliance | GMP / WHO-GMP / Schedule M hygienic design |
Plant Capacities
| Vessel Scale | Typical Use | Agitator Configuration | Operating Mode |
|---|---|---|---|
| Pilot-scale | Process trials, small-batch drying | Single paddle shaft | Batch |
| Production-scale | Commercial batch manufacturing | Single paddle shaft | Batch |
| Large production-scale | High-volume batch drying | Single paddle shaft | Batch |
Vessel volume and heat-transfer area are sized to the batch size, fill ratio and target drying time; exact capacity is configured to your process requirement.
Manufacturing Process
Charging
The wet solid or paste feed is charged into the horizontal vessel through a top port, sized to the batch volume required for the process.
Vessel Sealing & Vacuum Draw
The vessel is sealed and evacuated to the target vacuum level, lowering the boiling point of residual moisture or solvent for drying at a controlled, reduced temperature.
Paddle Agitation
The single internal paddle shaft rotates at low, controlled speed, continuously lifting and turning the product bed so it repeatedly contacts the jacketed, heated wall.
Jacket Heating
Hot water, steam or thermic fluid circulating through the vessel jacket conducts heat into the agitated product, evaporating moisture progressively through the batch.
Vapour Removal & Condensation
Evaporated moisture or solvent vapour is drawn from the vessel headspace under vacuum to an external condenser, where it is recovered and the vacuum level sustained.
In-Process Monitoring
Jacket temperature, vacuum level and paddle torque/power draw are monitored through the cycle to track drying progress and confirm the drying endpoint.
Discharge
Once dry, the product is discharged through a bottom valve, typically assisted by continued paddle rotation to sweep the vessel clear.
Cleaning & Changeover
The enclosed vessel is cleaned in place between batches, supporting validated changeover on multi-product lines.
Major Plant Equipment
- Horizontal jacketed drying vessel (SS 316L, electropolished)
- Single paddle agitator shaft
- Paddle drive motor, gearbox and mechanical seal
- Jacket heating system (hot water / steam / thermic fluid)
- Vacuum pump and vacuum receiver
- Vapour/solvent recovery condenser
- Top charge port
- Bottom discharge valve
- Instrumentation (vacuum, jacket temperature, paddle torque/speed)
- PLC-based control panel
Plant Output
Applications
- Batch drying of pharmaceutical and nutraceutical wet solids
- Drying of botanical extract granules and moderate-consistency pastes
- Food-grade powder and granule batch drying
- Chemical intermediate and specialty-powder drying
- Drying of filter cakes with moderate stickiness
- Solvent-wet solids requiring vacuum-assisted solvent recovery
- Small-to-mid-scale batch drying ahead of packing or blending
- Process development and pilot-batch drying trials
Key Features
Simple, Reliable Single-Shaft Agitation
A single paddle shaft keeps the product continuously moving against the heated wall, giving even heat transfer with a simpler mechanical design than a twin intermeshing-shaft dryer.
Vacuum Operation for Reduced-Temperature Drying
Drying under vacuum lowers the boiling point of moisture or solvent, protecting temperature-sensitive products and enabling solvent recovery via an external condenser.
Even Heat Transfer, No Static Dead Zones
Continuous paddle rotation repeatedly exposes the product bed to the jacketed wall, avoiding the localised overheating or under-drying that can occur in a static bed.
Straightforward Batch Operation
A single, well-defined batch cycle of charge, dry and discharge suits processors who need dependable, repeatable drying without continuous or semi-continuous feed handling.
Fully Enclosed, CIP-Capable Vessel
The sealed vacuum shell and CIP-capable design support clean changeover between products on multi-product batch lines.
GMP-Compliant Construction
Electropolished SS 316L product-contact surfaces meet WHO-GMP and Schedule M hygienic-design expectations for regulated batch manufacturing.
Frequently Asked Questions
What is a Vacuum Paddle Dryer used for?
How is this different from the RVPD (Rotary Vacuum Paddle Dryer)?
Why dry under vacuum rather than at atmospheric pressure?
What feed types suit a Vacuum Paddle Dryer?
Is the Vacuum Paddle Dryer suitable for solvent-wet products?
What capacity range is available?
What material of construction and compliance does the dryer meet?
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