Drain line: the hydraulic components leaked oil into the return pipe or tank.

泄油管路：将液压元件泄露的油液导入回油管或油箱。

Outdoor drains are subject to freezing temperatures which can obstruct the drain line.

室外排水口在冰冻气温下可能会冻结并堵塞排水管。

When installing a drain line, use Series 909 air gaps on Model 909 backflow preventers.

在安装排泄管线时，在型号909防回流阀上采用系列909气隙。

Vent the air gap and drain line from the relief valve in accordance with code requirements.

按照规程的要求，排出安全阀气隙和排放管道的空气。

A proper drain line connected to the valve outlet and run to a safe place of disposal must be installed.

必须安装一个适当的排泄管道，连接阀门的出水口，并且流向安全的地方。