The disc and associated moving parts may be in a constant state of movement if the velocity pressure is not sufficient to hold the valve in a wide open and stable position.

如果流体流速压力无法将阀门支撑在一个较大的开启度并保持在稳定的开启位置，则阀瓣和相关的运动部件可能会处于一种持续振动的状态。

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Two or four oil wedges uniformly spaced on the circumference hold the rotor in a stable position.

转子周边均匀分布的两个或者是四个油楔是转子处于一个稳定的位置。

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These are propellers mounted in transverse tunnels in the hull, to help position the craft and hold her stable while alongside a rig.

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