| 摘要 |
PURPOSE:To keep a magnetic fluid stably in a seal part as well as to improve sealability ever so better, by installing an annular projecting part in the side of a runner, and also installing magnetic circuits at both sides of the projecting part with both opposed, while making up a pocket part, which collects the magnetic fluid, on the tip. CONSTITUTION:In case of a hydraulic machine, for example, a Francis turbine, an annular projecting part 18 being projected in a horizontal direction is solidly installed in the upper peripheral part of a runner band 16. And, at the upper and lower surface positions of the projecting part 18, each of annular magnetic circuits consisting of a pole piece 19 and a permanent magnet 20 are oppositely installed in a state of supporting a lower cover 17. With this constitution, an interval between the runner band 16 and the lower cover 17 is sealed up with the magnetic circuit and a magnetic fluid 21. In addition, at the tip end of the projecting part 18, a pocket 22 for collecting the magnetic fluid 21 being splattered by centrifugal force attending on rotation in the runner band 16 is formed. According to this method, the magnetic fluid 21 can be stably held in the seal part, thus sealability is improvable. |
