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1·The emergency drainage device is an important device in floating roof tank, used to drain the overloaded water accumulated on the floating roof to ensure a safety for oil tank.

浮顶油罐紧急排水装置是浮顶油罐上的一个重要的附件，其主要作用是排出浮顶上的超载积水，保证油罐浮顶的使用安全。

2·Roof rain runoff areas may require a drain or gravel sump to protect plants and structures.

屋顶雨水径流的地区可能需要排水渠或砾石坑保护植物和结构。

3·Water came down from the roof through a small drain carved in the outside north wall of the grotto. It was led to a small pool which served to decant it before it flowed into the cistern proper.

水从屋顶沿著北边外墙挖的小水管流下来，形成一个小水池为协助它徐缓地流入更适合的贮水槽。

4·Applying long horizontal roof rock hole to drain the gas from adjacent seam and goaf is a new technique. In this paper, introduces the latest progress of this technique is introduced fully.

采用顶板岩层水平长钻孔抽放邻近层和采空区瓦斯是一项新技术，全面介绍了该技术研究的最新进展。