Room ventilation system has reversible electric motor drive motor drive and duplex fan to deliver heated air into room or to extract room air to exterior

摘要

The motor (10) has a fan (12) with blades (11) having two sections (11a,11b) with opposing direction angles so that the outer portion (11b) delivers air (15) into the room through an annular duct (8) and the inner sections (11a) extract air (5) from the room. A rotation direction sensitive baffle (32) closes off one or other of the air flow ducts (7,8). The direction of rotation of the motor is controlled by a bellows (19) and magnet (24,27) arrangement according to the heat exchanger tubing (17) and bellows volume.