活门的英文：
valve
Pack a valve stem.
扎好活门塞
n. 阀门；瓣膜；真空管
v. 装阀于；以活门调节
Valve Disadvantages: The valve is difficult to close and requires the operator to double close the valve.
阀门的缺点:阀门难以关闭，要求操作者二次关闭阀门。
pilot valve governor
带伺服电动机的调节器辅助调速器
The valve has jammed shut.
阀门给卡住了打不开。
multiple leaf valve
多簧片阀
cooled anode valve
冷板屏极真空管
底板活门的英文怎么说