| 摘要 |
A stationary ferrofluidic seal for sealing a stationary shaft to a rotating hub. A formed magnetic is attached to the rotating hub, bounded by upper and lower members to form a shaped cavity. A stationary ring is attached to the shaft and extends into the cavity, which is filled with a conductive ferrofluid. The cavity has a uniform, concave cross section over at least part of its surface. The end of the stationary ring distal from the shaft is shaped so that in the region containing the fluid, the ring and cavity surface are equidistant from a set of points defining the seals "characteristic contour". The seal's Power Index is defined as (AxRˆ 2)/(DELTAxV), where: A=surface area of the characteristic contour R=maximum radius of the contour about the axis of rotation DELTA=average gap between the inner and outer member V=total volume of the fluid Power loss is minimized by constructing the seal so that the Power Index is less than 700 (more preferably in the range of about 200 to 500).
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