TUNING IN TO BETTER DRYING.(description of radio frequency dryers)

Advances in radio frequency drying technology are increasing the efficiency and quality of the drying process.

Radio frequency (RF) dryers have been used by the ceramics and glass fiber industries since the early 1970s. Today, an increasing variety of advanced ceramic products, refractories and fiberglass materials are being processed in a new generation of advanced radio frequency drying systems appropriate for the modern factory environment. Reliable and user-friendly RF systems are being manufactured with state-of-the-art process control systems, readily enabling their integration into today's sophisticated production facilities.

Principle of Operation

In a radio frequency drying system, the RF generator creates an alternating electric field between two electrodes. 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 in the same way magnets move in an alternating magnetic field. The friction of this movement causes the water in the material to rapidly heat throughout the material's entire mass.

Figure 1 (p. 44) depicts a radio frequency drying system with a product between the electrodes. Polar molecules within the product are …