This welding backing is specially designed for hand holes and manholes welding.
本衬垫适用于入孔,出孔的焊接使用.
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Air investigations are absolutely necessary before entering any manholes.
空气调查是绝对必要的,方可进入任何沙井.
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Interior surfaces of manholes and its covers should level with that of the container.
人孔及人孔盖的内表面与容器的内表面平齐.
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Manholes are equipped with complete parts such as manhole covers , washers, bolts, nuts and lifting rods.
人孔配有人孔盖 、 垫圈 、 螺栓 、 螺母和起吊杆等全套部件.
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