| 摘要 |
PROBLEM TO BE SOLVED: To hold a seal condition for a long period, without deteriorating a magnetic fluid for a long period by filling a magnetic fluid seal between a shaft and housing, and interposing a buffer liquid whose specific gravity is larger than sealed liquid between the magnetic fluid seal and the sealed liquid. SOLUTION: A vertical type rotary machine is composed of a shaft 1, a sealed fluid 3, buffer liquid 7, and a magnetic circuit which consists of a pair of annular pole pieces 4, an annular magnet 5, and a magnetic fluid 6 in a housing 2. The buffer liquid 7 is interposed between a magnetic fluid seal and a sealed liquid 7, it is not mixed with the sealed liquid 3, and its specific gravity is larger than that of the sealed liquid 3. Perfluoropolyether oil or the like is used as the buffer liquid, however it is different in kinds of base oil of sealed liquid and magnetic fluid seal. Even when the sealed liquid is a nonfluorine solvent containing surface active agent and water, or electrolytic solution, the surface active agent is transferred to the surface of magnetic particle to prevent deterioration of a magnetic fluid. |
