| 摘要 |
The disc-shaped object (1) is movably mounted in a cavity (5) in the holder (2) which has a feeder (3) for liquid, especially for water, near the cavity. The peripheral rim (1a) of the object is mounted in the cavity. The rim on the parts of the object next to the side surfaces (1b,1c) of the object are rounded. The rotary axis (4) of the object coincides with the axis of symmetry of the object and is horizontal. Between the object and the cavity is a gap preferably 0.1 to 2, and especially 02, millimetres wide. containing the liquid. |
