短语词组短语oxycen on -off valve 氧气开关ON -OFF air valve 气动开关阀pneumatic on -off valve 气动开关阀;气动切断阀on -off ctrol valve 两位式控制阀的控制high -speed on-off valve 高速开关阀High Speed On -off Valve 高速开关阀 返回 on-off valve