Ventilation device for buildings equipped with a valve for opening and closing an aperture for the passage of an airflow

Air exchange device for buildings, comprising:

• a casing having an internal inlet opening, an internal outlet opening, an external inlet opening and an external outlet opening,
• a heat exchanger housed inside said casing and having a first inlet in communication with the internal inlet opening, a first outlet in communication with the external outlet opening, a second inlet in communication with the external inlet opening and a second outlet in communication with the internal outlet opening,
• a first fan unit arranged for generating a first airflow directed from the internal inlet opening towards the external outlet opening and a second fan unit arranged for generating a second airflow directed from the external inlet opening towards the internal outlet opening, wherein the first and second airflows are in a relationship of mutual heat exchange in said heat exchanger;
• and
• a valve device including respective valve elements for opening and closing the external inlet opening and the external outlet opening, wherein each of said valve elements comprises:
• a fixed crown gear;
• a rotatable crown gear;
• a flexible sleeve having a first end fastened to the fixed crown gear and a second end fastened to the rotatable crown gear;
• and
• an actuator for controlling the rotation of the rotatable crown gear with respect to the fixed crown gear between an open position wherein the flexible sleeve has essentially an annular shape and a closed position wherein the flexible sleeve has essentially a diaphragm shape.