The article introduces the technology of liquefied nitrogen freezing for the construction of the drain repairing of communication passage.

本文主要介绍了旁通道排水管修复液氮冻结加固施工技术，为今后类似排水管修复工程提供经验。

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When the water level of condensate in the drain sump drops, the cup to shut the admission pipe falls down, the passage for steam to enter into the valve body is opened.

由于通往阀腔的进汽管被密封，凝结水从集水仓流经进水管进入阀腔，倒吊桶下沉，打开排水阀嘴，周期性的开始排水。

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She leaned forward over the sink, unexpectedly dizzy, taking her weight on her arms, and staring down into the dark passage of the drain, understanding it for a few seconds as if it opened a way out of the world, or into it.

NEWYORKER: Friendly Fire