| 摘要 |
A rotating impeller for stirring liquids contained in tanks. Strip-like blades of simple form radiate from a central hub, in swept-back configuration relative to the direction of rotation. The blades are angled relative to the hub so as to exert a forward and downward force upon the liquid as the impeller rotates, and the blade curvature is such that the area projected upon the liquid by the solid structure of the rotating blade is less than the corresponding area that would be projected by an otherwise similar blade in which imaginary straight lines connected all adjacent vertices, and any void areas lying within the boundaries of those imaginary lines had been filled in. The preferred arrangement of the blades is such that when the impeller is arranged with its axis vertical, curvature of each blade along its length is such that it extends away from the hub in a diminishing downward curve, reaches a lowest point, and then rises again before the blade tip is reached. In cross-section each blade will typically be straight and parallel-sided, but may also be slightly curved, of aerofoil section, etc.
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