Meanwhile, the flap valve can be used to adjust weight, spring tension and the bottom outlet valve flap valve opening size to determine the pressure and open and close time.

同时，可以利用调整阀瓣的自重、弹簧的弹力以及阀瓣的底孔大小来确定阀门的开启压力和启闭时间。

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When the pressure difference changes with time, a phase shift will occur between the transient pressure difference and displace of valve flap, which could cause leakage and even reverse flow.

当阀片两侧的压差随时间变化时，阀片的启闭与压差的变化之间存在一定的相位差，有可能引起泄漏甚至反向流动。

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This valve is normally automatic work, in a direction of flow of fluid under pressure, open the flap valve;

通常这种阀门是自动工作的，在一个方向流动的流体压力作用下，阀瓣打开；

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These valves use a screw type valve instead of a simple flap, and they have a pressure regulating mechanism that will vent water to the ground if the intake pressure exceeds a set level.

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The device is a hinged flap connected to the sea-bed which uses wave power to deliver high-pressure water to an onshore turbine.

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