短語(yǔ)詞組短語(yǔ)pilot valve push stem 先導(dǎo)閥頂桿valve -stem leakoff 閥桿引漏valve plug stem 閥桿valve e stem 閥桿Valve -stem sealing 氣門(mén)油封emergency valve piston stem 緊急閥活塞桿 返回 valve stem