大口径螺旋焊接钢管
Large -sized spiral welded pipe
双层保温管
double-layer and insulated pipeline
大口径管材
large diameter pipe
large caliber winding pipe
large caliber pipe
小管径螺旋埋弧焊管
Small-sized spiral submerged-arc welded pipe
三层双螺旋
three-layer double spiral
双管双层分采完成井
two-tubing dual completion well
双管双管板换热器
double tube double tube-plate heat exchanger