In a tunnel dryer, materials are placed on trays loaded onto drying carts, which move forward through the tunnel for the drying process; loading and unloading take place at opposite ends. Typically employing counter-current or combined counter-current/co-current airflow, the system offers high loading capacity, allows for sequential unloading, ensures consistent product quality, requires low investment, and is easy to operate.
It is primarily used for drying agricultural and sideline products (such as fruits and vegetables), traditional Chinese medicinal herbs, and pet food. Utilizing hot-air convection heating, the process ensures the product remains completely free from contamination, fully complying with food hygiene standards. The hot air can be recirculated, significantly enhancing thermal efficiency. Drying trays can be made of plastic or stainless steel mesh, or constructed from materials such as wooden slats, wire mesh, bamboo netting, or screens, offering great flexibility and convenience.