Abstract: Device for reversing an air flow in a drying chamber in which the air flow is created by at least one blower. A drum, rotatable about its longitudinal shaft is arranged about the blower or blowers. The drum has apertures on its casing surface to provide an air flow through the drum. The drum extends from the floor of the drying chamber to its roof, or is sealed in another way at its ends. By rotating the drum about its longitudinal shaft between two different positions, a reversal of the direction of the air flow in the drying chamber is achieved in a very simple way, although the blower is stationary and drives the air continuously in the same direction. A heat battery is arranged on the intake side of the blower.