Respiratory device has an impeller mobile around an axis housed in a surrounding casing, the air passageway decreases in size between the air inlet and the entry of the impeller casing where the diameter is suddenly much larger

摘要

Air blowing device has an impeller (2) mobile around an axis (7) housed in a surrounding casing (3). The air passageway decreases in size between the air inlet (1) and the entry of the impeller casing where the diameter is suddenly much larger.