(1) Copper tube, stainless steel tube;
(2) Steel pipes that have been pickled before pre-installation and are now free of rust and scale on the inner wall;
(3) Pipe joints that were soiled during pre-installation;
(4) Remove the pipe and joints to be cleaned, wipe the inside of the pipe with cloth (not to lose wool yarn) dipped in kerosene, clean the ends and joints in kerosene, then coat the pipe with engine oil or fill with grease, two The end is tightly closed for installation;
(5) After cleaning, there must be no visually visible contaminants (such as iron filings, fibrous impurities, welding slag, etc.). Pay special attention to the inner wall welding slag of the welding place must be thoroughly cleaned.