套管出线装置安装
installation of valve bushing turrets
手动控制阀输出管线
hand control valve outlet line
X80电阻焊管线管
X80 grade electric resistance welding linepipe
地下管线管理
underground pipeline management
Management of Underground Pipelines
地下管线管理系统
underground pipeline management system
钩形集极晶体管管线
hook collector transistor