Second check must be drip tight when pressure is applied to downstream side of valve.

当阀门下游一侧出现压力时，第二止回阀必须是无滴漏。

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Second check must be drip tight when pressure is applied to downstream side of valve.

当阀门下游一侧出现压力时，第二止回阀必须是无滴漏。

youdao