lower valve seat的意思|示意

Rotate one half of the valve body 180o making sure the lower valve seat and oring stay in position.

将阀体的一半旋转180o，确保较低的阀座和O形环留在位置上。

The lower stem is encased in a spring which forces the stem away from the seat when the valve is opened.

当手轮象开启位置旋转时，上阀杆离开横膈膜，弹簧推动下阀杆离开阀座。

A spring on the valve stem tends to hold the valve on its seat (closed). The lower end of the spring rests against the cylinder head.

气门杆上的弹簧使气门保持在气门座上(关闭状态)。弹簧的下端抵在气缸盖上。