| 摘要 |
754,055. Centrifugal fans. WESTING- HOUSE ELECTRIC INTERNATIONAL CO. Aug. 3, 1954 [Aug. 5, 1953], No. 22448/54. Class 110(1) [Also in Group XXXIII] A centrifugal fan wheel comprises a back plate, a side plate, a plurality of curved aerofoil blades secured between said plates and means for preventing boundary layer flow separation at very high and very low gas volumes comprising openings in the inner and outer sides of the blades through which gas can move as a result of the rotation of the fan wheel. The wheel has a curved side plate 20 and a back plate 21 connected to a hub 22 with curved blades 23 attached at their ends as by welding or riveting to the back and side plates. Each blade has slots 24 extending therethrough from points in the outer side of the blade to respective points nearer the trailing edge of the blade in the inner side. the difference in pressure on the two sides causing the gas to flow into the slots at the outer side and out at the inner side to draw away and sweep turbulent flow from the respective sides. In another embodiment the inclination of the slots-through each blade is opposite to that shown in Fig. 2 and in further embodiments each blade is hollow and both surfaces are perforated and an aperture is provided in the plate 21 within the profile, and adjacent the trailing edge, of each blade or in the trailing edge of the blade itself whereby gas is drawn into the interior of the blade and exhausted at the trailing edge. |
