Buried depth of rain water pipe should be buried in the frozen line, consideration should be given to the upper part of the load pipeline.
埋地雨水管的埋没深度应在冰冻线以下，应考虑管线上部的荷载。
2
Oil temperature drop and oil contraction can cause gas space growing in oil pipe and line packing during hot oil pipeline shutdown and restarting.
热油管道停输后，管内油品降温收缩，管内会产生油蒸气空间，从而使管道再启动时出现启动充装过程。
3
Then combined pipe-line theory, the accumulator's integrated mathematical model with incurvate and strange diameter series connection pipeline is built.