Abstract: A thermo-pneumatic unit for thermal treatment of moving flat materials such as a drying process for cowhides includes a blower which is located on one side of the travelling path of the materials and adapted for generation of thermally adjusted air flow having specified initial direction and mass velocity distribution so that larger mass velocity is focussed upon the portion of each material requiring higher rate of thermal treatment. Ideally, an even thermal effect is obtained over the entire parts of each material and thermal energy loss is effectively avoided even when the material has initial local variance in moisture content or temperature. A collector for blown air on the other side of the travelling path collects the blown air, which assures higher evenness in thermal effect with less thermal energy loss.