The special active agent content makes suitable herbals for healing and health preservation. The key element in herbs and spices processing is drying. The required low moisture content of medicinal plants to storage can be achieved only by applying drying equipment at Hungarian climatic conditions. The extent of the dryer capacity defines the processing capacity of the factory. During the daily operation can easily occur bottleneck, when large amount of herbs are transported to the factory, which is above the drying capacity — various plants unexpected simultaneous flowering, weather emergency, extraordinary collecting, etc. The aim of the manuscript is to determinate operational data at herbs pre-drying with low temperature air by measurements. This work defines the drying rate, the volume decrease and the drying air velocity for various medicinal plants at drying with ambient air.
passive techniques together while the enhancement results that reached by the various active methods, like vibration surface, will not be mentioned unless mentioned with a passive category in this manuscript. The passive methods can be summarized by how