求翻译：④ 在良浆出口管的底部开口，设冲洗/排空管并带有阀门，分别接至清水管线及排污管线，平时关闭，停机冲洗及排污时开启。是什么意思？

④ accepts export opening at the bottom of the pipe, set flush/drain pipes with valves, respectively to the clear water pipelines and sewage pipelines, usually closed, stop irrigation and sewage opens.