Keskipakopuhallin

摘要

A fan has a spiral-shaped casing in which is mounted the fan impeller consisting of a carrying disk (6) and a cover disk (7) between which are secured blades (8). The entrance angle of each blade (8) increases from the carrying disk (6) towards the cover disk (7). The curved lateral surface (12) of each blade (8) has the form of a linear unrolling surface with their generatrix (16) inclined to the plane perpendicular to the axis of the fan impeller at an angle ( alpha ) between 45 and 85. The projection (17) of at least one of said generatrix on the plane perpendicular to the axis of the fan impeller is a tangent to the section (13) of the curve obtained as a result of intersection of the lateral surface (12) of the blade (8) by said plane.