CENTRIFUGAL FAN (VERSIONS) Russian patent published in 2008 - IPC F04D17/08 F04D29/66 

FIELD: engines and pumps.

SUBSTANCE: fan incorporates scroll case 1, impeller 2 with blades 8 and front disk 7, inlet manifold 4 with cylindrical section 16, inlet branch pipe 5 equal to width L of casing 1, annular gap 11 between the surfaces of manifold 4 and disk 7. Blades 8 are furnished with leading-edge flap 17 arranged between the abutment of blade 8 to the surface of front disk 7 and axis 13 of impeller 2. Here note that the straight line connecting axis 13 and tip 20 of leading-edge flap 17, in a plane projection perpendicular to axis 13, does not extend beyond a sector limited by rays located in the range of ± 0.05 of the blade angular pitch t relative to the straight line connecting axis 13 and point 21 of the abutment of front leading-edge 18, the next along the rotation of blade 8A, to the surface of front disk 7. In compliance with the first version, plate 12 of vortex arrester, its height making h_Va=H_Va=10...0.12, is arranged on outer surface 9 of manifold 4 between the meridian planes crossing the line of complete opening of casing 1 and shifting by 45° from the aforesaid plane towards cut-off sheet 14. In compliance with the second version, plate 24, its height making h_pS=H_pS/D=10...0.14, is connected to casing 1 opposite to blades 8 between the meridian planes crossing the line of maximum opening of casing 1 and tip 25 of cut-off sheet 14.

EFFECT: higher pressure characteristic and efficiency in the operating area with lower noise at the fan inlet at the blade frequency and its harmonics.

9 cl, 19 dwg