摘要 |
An anemometer for measuring the component of air or of a similar fluid speed along its axis of rotation, in which the anemometer has a plurality of generally radially directed, helicoidal airfoils. The airfoil effect is produced by the helicoidal twisting which results in a vacuum being produced on one side thereof according to the direction of rotation. Each of the airfoils has a plurality of helicoidal edges, each edge being formed by the intersections of two or more plane surfaces so as to form airfoils having parallelogram or substantially parallelogram cross-sections. Each airfoil extends outwardly from a rotatable hub and is attached to the hub at its inner end but is spaced in part from the hub by a cutout area, such as a slot across the airfoil.
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