To test for tightness of second check Valve.

检测第二止回阀的密封性。

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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。

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These valves are referred to as second generation diaphragm valves because basic changes in the valve design have been incorporated to resolve the deficiencies of the earlier diaphragm valves.

因为阀门设计产生了基本的变化，以克服较早的隔膜阀的缺点，这些阀门被称为第二代隔膜阀。

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The second would study valve-in-valve TAVR procedures.

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Later that year, a second study in patients with a heart valve problem also failed to show a benefit.

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The rocket launched without a hitch following a flawless countdown that came three days after a faulty valve on one of the rocket's engines forced a last-second postponement.

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