Patent attributes
A blower for a respiratory apparatus includes an impeller configured to rotate to pressurize the supply of gas. The impeller includes a shroud with a plurality of vanes extending from a surface of the shroud toward the gas inlet. Each vane radiates outwards from a hub in the shroud that is configured to receive a motor shaft. The outer diameter of the shroud varies between maximum portions with a maximum outer diameter and minimum portions with a minimum outer diameter. The maximum portions are located at the vanes and the minimum portions are located between the vanes. In addition, each vane has an intermediate point located a predetermined distance from the hub that marks the beginning of a curvature of the vane in the direction of the impeller's rotation. The curvature of the vane is located between the intermediate point and the radially outermost end of the vane.
