| 摘要 |
An apparatus has a tank with an open top, a tank wall, and a closed bottom. A first ringwall extends from the bottom such that a first annular space is defined by the first ringwall and the tank wall, and a second annular space is defined by the first ringwall. A second ringwall extends in the second annular space and defines a third annular space between the first ringwall and the second ringwall and further defines a cylindrical space. A conduit extends into the cylindrical space. A pod disposed into the cylindrical space has a closed chamber and a displacement chamber. An inner riser disposed in the third annular space has an open bottom, and an outer riser is disposed in the first annular space and has a closed top, a wall, and an open bottom. |
