Continuous Vacuum Dryer Improves Product Quality
Artisan’s Rototherm® D is a specialized slow-speed dryer designed for continuous vacuum drying or post-drying of free-flowing solid materials.
It Offers The Following Benefits Over Batch Dryers:
- Batch dryers have no shear
- Low temperature and shear reduce product degradation
- Continuous process eliminates variations in product quality between batches
- High heat transfer area-to-volume ratio
- Adjustable drying time from 20 minutes to several hours
Rototherm® D is a jacketed, mechanically-agitated dryer that continuously removes moisture or solvents from powders and bulk solids under vacuum. It is especially useful for diffusion-limited drying applications where long residence times are required.
Rototherm® D Operating Principle
Moist powder or bulk solids are fed into Rototherm® D at one end. The horizontal shell and the specially designed rotor are heated by water, steam, or hot oil. The product is agitated at low speed by the helical mixing bars, gently churning and continuously conveying it to the discharge end of the dryer in a plug flow manner.
Vacuum minimizes drying temperature and avoids thermal degradation of heat sensitive materials. An adjustable weir at the discharge end keeps the product level in the dryer between 25% and 75% full. The residence time is controlled by adjusting the height of the weir or changing the feed rate.
The dry product discharge is collected either by batch in a sealed vessel or continuously after passing through a vacuum lock vessel.
Artisan’s Rototherm® can produce a dry solid directly from a solution in one unit operation. It gives you the ability to dry materials that are heat sensitive, viscous and prone to foaming. You can dry solutions, slurries or wet cakes to free-flowing powder. And Rototherm® is simple to operate.
Dry Slurries & Solutions with Dissolved or Suspended Solids
For these applications, Artisan recommends our Rototherm® P. It is a horizontal, continuous thin-film evaporator designed to handle a wide range of difficult drying applications. Each unit is designed to meet specific customer and application requirements.
Application: Drying Animal Protein
Produce a free flowing powder from an aqueous animal protein solution without denaturing the protein.
Artisan’s Rototherm® P, a mechanically agitated thin-film processor, is widely used to produce free flowing powders from a variety of heat sensitive products. Rapid heat transfer, plug flow, and extremely short residence time make it the most versatile “single step” processor in the industry.
Rototherm® P is used to dry aqueous solutions of animal proteins with an initial composition of 93% water and 7% animal protein. The material is dried under vacuum to a free flowing solid product. The short residence time in Rototherm® P prevents thermal denaturing of the protein. And since a thin-film is created in Rototherm® P without direct contact between the rotor and the wall, shearing and/or mechanical denaturing of the protein is prevented that would otherwise occur in a scraped surface evaporator.
Dry Wet Cakes or Semi-Dry Solids
For these applications, Artisan recommends our Rototherm® D. It is a specialized, slow-speed unit designed for continuous vacuum drying or post-drying of free-flowing solid materials. Rototherm® D is ideal for diffusion-limited drying applications where residence times of up to several hours are required.
- Drying heat sensitive powders and bulk solids
- Drying shear sensitive powders and bulk solids
- Diffusion controlled drying applications
- Further de-watering readily dried sludges and presscakes
- Sublimation of powders
- Solid state polymerization/polycondensation