After the installation of refrigeration equipment, it is inevitable that there will still be welding slag, iron filings, oxides, sand and other residues inside the system. In order to avoid damage to the valve and unit, and to avoid clogging of the filter and pipeline, it is necessary to clean the unit before operation. Pressure gas is usually used to blow out the pipeline and system for sewage discharge, with a blowing pressure of 0.6MPa. The blowing work can use compressors, air compressors,