Requirements: Valve must be tight against reverse flow under all pressure differentials.

要求：在所有压差下，阀门对于回流必须是密封的。

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Requirement: Valve must be tight against reverse flow.

要求：这种阀门对于回流必须密封紧密。

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The Bi-Directional Knife Gate Valve provides bubble tight shutoff in both directions up to full rating of the valve.

这种双向刀闸阀在阀门压力等级下，任何方向均可实现气泡级密封关闭功能。

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Xi3's Piston is the first such creation revealed, though the company's staying tight-lipped about specs -- we do know that Xi3's working directly with Valve on its tiny, modular PC.

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