短语词组短语flat slide valve 平滑阀;平座阀平滑阀闸阀;平座阀balanced flat slide valve 自动平衡平滑阀flat seat valve 平座阀flat throttling valve 平面节流阀flat head valve 平头气门flat check valve 平面型单向阀flat headed valve 平顶气门Imported Flat Gate Valve 进口平板闸阀 返回 flat valve