An air distribution device. The air distribution device an air distribution chamber arranged to receive a flow of ventilation air from the air outlet. The air distribution chamber further having one or more perforated throttling plates or meshes perpendicular to the inner perforated wall and perpendicular to the flow of ventilation air from the air outlet into the air distribution chamber. The air distribution device also includes a pressure equalization chamber formed between an inner air permeable front plate of the air distribution chamber and an outer front plate. A perforation-free area of the outer perforated front plate is smaller than the perforation-free area of the inner perforated front plate in order to equalize ventilation air pressure in the equalization chamber and to provide a uniform flow of air through the outer front plate.