| 摘要 |
<p>A vacuum drainage system (12) having a vertical riser (16) with an aeration point (10,30). The aeration point prevents stalls in the vacuum drainage system by breaking up the formation of a solid fluid column in the riser (16). In certain applications, the aeration point allows the vacuum drainage system to operate in a deliberately flooded condition by regulating air flow into the riser. The aeration point (10,30) may be provided simply as a hole positioned at an optimum height (H) above a bottom of the riser, or it may include apparatus (10,30) for retaining fluid inside the riser (16), such as a check valve. In addition, the aeration point (10,30) may be provided with an automatically adjustable cross-section, so that the aeration point is quickly and easily adapted to changing operating parameters in the vacuum drainage system. <IMAGE></p> |
