| 摘要 |
PURPOSE:To cut off the leakage of a gas such as steam from a gap by interposing a plurality of magnets having a center hole into which the shaft of a turbine is inserted in a ground housing in the axial direction at a predetermined interval and sealing a magnetic fluid into the gap between the magnets and the shaft of a turbine. CONSTITUTION:In the state of interposing a plurality of permanent magnets or electromagnets 6 which are molded into a hollow disk form by a plurality of pole pieces 7 made of a low carbon steel plate or a silicon steel plate, the permanent magnets or the electromagnets are contained in a ground housing 3 through an insulating box with the polarities alternately inverted and at a predetermined interval in the axial direction. At that time, a gap S2 is formed uniformly in the circumferential direction between the inner circumference of hollow disk-form pole pieces 7 and the shaft 1 of a turbine, and a magnetic fluid 9 is sealed thereinto by magnetic force. A magnetic circuit 10 is formed among the electromagnets 6, the magnetic fluid 9 and the shaft 1 of a turbine, thereby sealing the gap S2 against centrifugal force and shearing force by means of the magnetic fluid 9. |
