RADIAL IMPELLER AND AIR DUCT FAN WITH THE SAID IMPELLER Russian patent published in 2008 - IPC F04D29/28 F04D29/66 

FIELD: engines and pumps.

SUBSTANCE: impeller incorporates front 1 and main 2 disks, bent off blades 3, shaft 9. Blade 3 has main section 7 abutting by edge 8 on disk 1, leading-edge flap 10 with front edge 11 lying in the plane perpendicular to shaft 9 and side edge 12 arranged at an acute angle to edge 11. Plane projection perpendicular to shaft 9 has a straight line connecting the said shaft 9 and tip 13 of leading-edge flap 10 and lying in the range of ± 0.05 of angular pitch of blades 3 relative to the straight line connecting shaft 9 and point 14 of intersection of edge 8 of nest blade 3A with disk 1. The fan incorporates casing 17 with air duct 21 having a cylindrical surface between walls 22, aforesaid impeller 19, inlet manifold 20, air duct 21 cross section exceeds that of impeller 19, at least, 2.4 times. Impeller 19 allows decreasing the noise level not only at the fan inlet, but at its outlet as well. Cross section of air duct 21 can have any shape, including a rectangular one, with a gap between blades 3 and long walls equal to, at least, 1.01 diameter of impeller 19. The fan can incorporate an additional impeller and a partition between impellers.

EFFECT: lower impeller and fan noise with aerodynamics intact.

12 cl, 21 dwg