Rotary Vacuum Dryers

Rotary Vacuum Dryers (RVDs) are specialized drying systems used for efficiently drying heat-sensitive, hygroscopic, and volatile materials under vacuum conditions. These dryers are ideal for industries where gentle, uniform, and low-temperature drying is essential—such as pharmaceuticals, chemicals, food, and biotechnology.

The design of an RVD features a rotating cylindrical vessel mounted horizontally, which is jacketed to allow for indirect heating through steam, hot water, or thermal oil. Internally, lifters or paddles continuously agitate the material, ensuring maximum surface area exposure and efficient drying. The rotation prevents material clumping or crust formation, promoting homogeneous drying throughout the batch.

At Harsha Engineers India, our Rotary Vacuum Dryers are engineered for precision, durability, and process reliability. They are fabricated using high-grade stainless steel (SS316/SS304) or carbon steel, depending on application needs. Our RVDs can also be equipped with solvent recovery systems, dust filters, mechanical seals, and automation controls for enhanced efficiency and safety.

Material of Construction (MOC): MS, SS 304, SS 316, SS 316L, Hastelloy, or Alloy steels (as per process).
Capacity Range: 50 Liters to 20,000 Liters (custom-built).
Design Pressure (Shell): Full vacuum to 1.0 bar.
Design Pressure (Jacket): Up to 3–6 bar for steam, hot water, or thermal oil.
Design Temperature: -20°C to +200°C (depending on heating medium and MOC).
Drying Mechanism: Indirect heating through jacketed cylindrical shell.
Agitator Type: Paddle-type with forward & reverse motion for uniform drying.
Drive System: Motor with gearbox, chain/belt drive, optional VFD (variable frequency drive).
Heating Medium: Steam / hot water / hot oil.
Moisture Removal: Vacuum system for rapid evaporation and solvent recovery.
Surface Finish:
- Internal: Mirror / matt polish (Ra 0.28–0.4 µm for GMP applications).
- External: Matt finish / painted / SS cladding.
Discharge: Bottom discharge with valve / automated discharge system.
Mounting: Horizontal, cylindrical with saddle supports.
Insulation: Mineral wool or ceramic fiber with SS or aluminum cladding.
Nozzles & Ports: Vapour outlet, solvent recovery line, feed inlet, discharge valve, manhole.
Safety Features: Vacuum relief valve, rupture disc, and interlocks for safe operation.
Compliance: ASME, GMP, DIN, and international standards.

A Rotary Vacuum Dryer operates by heating the product indirectly through a jacket while rotating a cylindrical vessel under vacuum. The material is constantly agitated by the rotation, which exposes new surfaces for drying and prevents clumping. The vacuum lowers the boiling point of liquids, making it possible to dry them quickly and with less energy at lower temperatures—ideal for products that are delicate.

Drying of APIs, intermediates, and heat-sensitive compounds for the pharmaceutical industry.
Drying powders, flavors, and herbal extracts for the food industry.
Dyes, pigments, and other specialty chemicals are dried in the chemical industry.
The drying of biological and fermentation products is known as biotechnology.

Energy-efficient drying at reduced temperatures.
Protects sensitive products from oxidation and degradation.
Ensures that the product is evenly dried and of high quality.
Low-maintenance design with easy operation.
Built specifically to meet specific industrial needs.

Conclusion

Rotary Vacuum Dryers from Harsha Engineers are the ideal choice for industries requiring efficient, contamination-free, and gentle drying solutions. With robust construction, customizable options, and adherence to industry standards, our RVDs deliver high performance, reliability, and long service life.