| 摘要 |
There is described a centrifugal fan comprising a radial impeller (2) and a manifold (4) for receiving the impeller, with at least one intake cross- section (5) and at least one outlet cross-section (6) for the flow which is produced by the impeller, the impelier (2) being provided so as to be moved in rotation about an axis of rotation (X), the intake cross-section (5) and the outlet cross-section (6) being provided near the axis of rotation and in a position remote from that axis, respectively. The impeller (2) comprises a plurality of substantially radial blades (3) which extend in an axial direction between a disc (7) and a counter-disc (8) which are fixedly joined to the blades and which define, together with the blades, corresponding conduits (9) which extend between the intake and outlet cross-sections, the counter-disc (8) extending between those cross- sections (5, 6) with spacing from a wall (11) of the manifold (4) facing it, and wherein the counter-disc (8) is provided with at least one through-hole (15) through the counter-disc so as to place each conduit (9) of the impeller (2) in fluid communication with the spatial region (13) defined between the counter-disc (8) and the wall (11) of the manifold facing it. |
