WRH-500A commercial food dehydrator use a rack structure. The material to be dried is placed on the rack structure and then moved into a drying house. The design of the rack structure depends on the airflow pattern and material placement. Based on real application, dispersing, penetrating and parallel airflow patterns can be chosen. If the material (such as longan, betel nuts) has a large volume or is loose, and is not easy to deteriorate even being piled with 30cm-50cm thickness, we can pile the material up using one single tray to improve productivity. Note: The above method can only be used for material that will not stick together during the process. Otherwise, the stuck material will block the airflow and the commercial food dehydrator will shut down automatically.