| 摘要 |
PURPOSE:To provide a high level shaft sealing effect all the time by constructing a shaft which is extending through a stratum investigating probe casing in such a manner that the pressure acting upon both sides of a magnetic fluid seal sealing said shaft is nearly equal so as to eliminate a differential pressure across the sides of said seal. CONSTITUTION:A magnetic fluid seal 3 is attached in a position in a stratum investigating probe casing 1 where a rotating shaft 2 is routed in a watertight manner by a lock 5 nut having O-rings 4a, 4b. Said rotating shaft 2 is supported by a bearing 6, and is extended from an output section of a rotary machine 8 such as a motor or generator which are installed in a closed space 7. The closed space 7 is filled with insulating oil such as silicon oil, and a side wall of the casing 1 comprising the closed space 7 is provided with an opening 11 which is closed by a pressure balancing bellows 12. In this manner, since in response to a water pressure P acting upon one side of the seal 3 the bellows 2 deforms to cause the pressure in the closed space 7 to become nearly P, the differential pressure across the sides of the seal 3 is eliminated, resulting in a high shaft sealing effect. |
