| 摘要 |
1,033,502. Mixed-flow blowers. GENERAL DYNAMICS CORPORATION. Feb. 13, 1963 [Feb. 15, 1962], No. 5831/63. Heading F1C. In the blower shown, the outer casing 10 is cylindrical but the impeller hub 14 increases in diameter in a downstream direction. Where the impeller blades 16 are each divided into two overlapping portions with a slot 24 between them, as described in Specification 872,228, the ratio between the relative velocity of flow at the trailing edge of the blade to that at the leading edge is between 0À65 and 1À1 at the hub, between 0À45 and 0À85 at the tip and has a mean value between 0À55 and 0À95. Where the blades 16 are of non-slotted form, these limits are 0À8 and 1À1, 0À60 and 0À85, and 0À7 and 0À95 respectively. The ratio of hub diameter to tip diameter at the trailing edge may be greater than 0À60. Non-slotted blades 16 may be of aerofoil or laminar form. Guide vanes 20 may be of slotted or laminar form and the inner casing 18 may be tapered to provide an increasing flow area in the downstream direction. The blades 16 and vanes 20 may be of substantially constant camber and chord and substantially without twist, and may operate with free vortex or forced vortex flow. The invention is also applicable to stator blading. |
