Method of purging air from a structure to be welded using liquid cryogen

摘要

In order to shorten the time period needed for the oxygen concentration to be reduced to about ten ppm, a method for purging air from a structure (10;40) to be welded is proposed, said method comprising feeding a liquid cryogen to said structure (10;40) wherein said liquid cryogen will expand to a gaseous state and displace (25) said air in said structure (10;40).