The valve may have a pair of helper springs urging the valve closed.

所述阀可以具有一对推动阀关闭的辅助弹簧。

youdao

Do not let pump run for long in the circumstance of discharge valve closed.

注意不要在排出阀关闭的状态下长期运转。

youdao

Keep return piping valve closed until trap fills with condensate. Slowly open valve.

保持回路管道阀门处于关闭状态直到疏水阀充满冷凝物为止。慢慢开启阀门。

youdao

But for many of Mr. Refaat's counterparts, the global recession of the late 2000s closed an escape valve for Egypt.

WSJ: Arab World Built Colleges, but Not Jobs

Argentina's economic difficulties have closed off Paraguayans' traditional safety valve of migrating south.

ECONOMIST: Paraguay��s coming crunch