Radio Frequency Vacuum Dryer

• Conventional thermal processes rely on surface heating by convection, conduction, and/or radiation with subsequent diffusion of heat into the material interior. This is a slow and expensive process because the material does not conduct heat and all energy has to be distributed throughout the material mechanically by complex mixers or sprayers, etc. inside the evacuated vessel.
• An alternative method, tried many times, is the application of microwave energy. Because the generation of free radicals in local plasmas (which attack most materials) and hot spots cannot be controlled, microwave energy is not a valid alternative.
• With radio frequency, the long wavelength of 11m (27.12 MHz) allows for an even evaporation energy distribution throughout the material. Hot spots do not occur and there are no free radicals degrading your product quality. The material to be dried is conveyed between the electrodes where the alternating energy causes polar molecules in the water to continuously re-orient themselves to face opposite poles much like the way magnets would move in an alternating magnetic field. The friction of this movement causes the water in the material to rapidly heat throughout its entire mass. Colpitt succeeded in completely avoiding plasma generation and the process does not require mixers inside the container. The dryer is extremely suitable in the pharmaceutical production industry: for the drying of medicine, vitamins (and even proteins), herbs, algae and most other delicate materials. 

Advantages to RF vacuum dryer:

• Drying temperature is +/- 35 degrees (minimal product degradation)
• Distribution of evaporation energy very evenly throughout the product
• The product is dried inside a detachable container (cleaning and handling advantages)
• No re-crystallization of the product (homogenous mixture avoids problems in further process steps)
• Most materials dry without a mixer
• No plasma, no free radicals
• Short batch cycle time (FDA paperwork for fewer workforce shifts per batch)

The radio frequency energy vacuum dryer is available in 3 different models:

• 1 liter (R&D model)
• 75 liter
• 200 liter

200L model

Colpitt has more than 60 years of experience with high frequency technology and has been building machines for medical applications for more than 40 years.