Closed type circular washing construction method of large pipeline

The invention relates to a closed type circular washing construction method of a large pipeline, and belongs to the technical field of pipeline washing. The influence of rust stain washing of a pipeline system used for the first time and conventional pipeline washing at the normal operation years on an air conditioner system in the prior art is overcome. The method comprises the following steps of conducting design analysis on the pipeline system, determining a pipeline washing sequence, making a temporary washing measure, determining parameters of washing equipment through hydraulic calculation, determining a sewage drainage and washing water filling scheme, perfecting water supply and drainage matched measures, conducting washing on different segments and different portions, conducting washing on individual dead corner pipelines, and conducting formal overall hydrostatic testing and circular washing on the pipeline system. A same-floor drainage system is adopted, so that operation is convenient during const