重型炼化设备筒体直径较大，筒体对接焊接后，对对接焊缝进行射线检测（单壁透照）时，无法有效观测到透照的整体布置，造成筒体焊缝内部的分区和外部分区不一致，黑度很难符合标准的要求而需要返工。为解决这个问题，提出了利用水平仪和激光测距仪寻找筒体最低点的设想并进行试验，结果表明，该方法能准确地对筒体对接焊缝进行分区，值得进一步推广。

The diameter of the barrel of heavy refining equipment is large. After the barrel is butt welded, when the butt weld is subjected to radiographic inspection (single-wall transillumination), the overall arrangement of the transillumination cannot be effectively observed, resulting in the division and internal division of the weld of the barrel. The external partitions are inconsistent, and the blackness is difficult to meet the requirements of the standard, resulting in rework. In order to solve this problem, the idea of using a level gauge and a laser rangefinder to find the lowest point of the cylinder is proposed and tested. The results show that the method is accurate for the butt weld zone of the cylinder and is worthy of further promotion.