To prevent water damage, the valve must be properly connected to a discharge line which terminates at an adequate drain. 为了防止水的破坏，这些阀门必须与排水管道连接，以便能够将水排到适当的排水口。
The city was even equipped with a drainage system, for many clay pipes were found beneath its narrow streets. 城里甚至还敷设了排水系统，因为在狭窄的街道底下发现了许许多多陶土制作的排水管道。
