Abstract: A dryer having a drying chamber and an inlet housing structure wherein a heating device is located in the inlet housing structure. An outlet structure is provided with a main chamber and a secondary chamber wherein the flow of gas exiting the drying chamber is divided into a main flow of gas passing from the main chamber to the inlet housing structure and a secondary flow of gas passing from the secondary chamber past a condenser which is located in the secondary chamber to the inlet housing structure. Side chambers located in the housing have side walls which are formed from a perforated sheet of metal. The dryer will function in a recycled-air operation as well as a fresh-air operation.

Abstract: A novel tray drying chamber having a tray-truck is provided, wherein moist material supported on the trays supported on the tray-truck are dried by the gas circulation method. The tray-truck and the drying chamber proper are constructed to form a functional unit, wherein the chamber-walls temperature controllable chamber walls and functionally cooperate with the external parts of the tray-truck to define gas-conducting passageways.