Patent Number: 6,305,694

Title: Ferrofluid sealing device

Abstract: A ferrofluid sealing device retaining a ferrofluid between a shaft and a pair of inner and outer pole pieces rotating in opposite directions, in which grooves are formed on a shaft surface that faces the inner diameter surfaces of pole pieces. In the sealing device, one of the pole pieces may be made thicker than the other and further a projection portion can be formed on the shaft surface facing the inner peripheral faces of the pole pieces. The sealing device can prevent, even when the ferrofluid seal is operated at a higher rotation speed, splashing of ferrofluid over the surroundings, thereby avoiding staining the surroundings as well as prolonging its lifetime.

Inventors: Yamazumi; Noboru (Asahi, JP), Unozawa; Heiichi (Chiba, JP)

Assignee: Ferrotec Corporation

International Classification: F16J 15/40 (20060101); F16J 15/43 (20060101); F16J 015/43 ()

Expiration Date: 10/23/2018