HIGHFREQUENCY DRYING OF POROUS MATERIAL

Highfrequency drying of a porous ceramic has been studied experimental ly. The influence of electrode voltage, electrode distance, electric c onductivity of the moisture and geometry of the product on the drying rate was investigated. There exists an optimal conductivity for maximu m power dissipation and the geometry of the product has a focusing eff ect on the electric field. A theoretical discussion concludes, that th e eddy current free quasi-stationary field is the type of field common ly present in highfrequency drying. With this type of field and the fa ct, that the complex permittivity of the product changes during drying , the experimental observations can be understood. From theory and exp eriment, conclusions are drawn in respect to a typical drying curve at highfrequency drying.