A steam generator having a steam generator chamber, a tube plate bordering the chamber, tubes terminating in the tube plate being accessible through the steam generator chamber, a tubular column in the steam generator chamber having an end facing toward the tube plate, and a swivel arm extended from...http://www.google.de/patents/US4649989?utm_source=gb-gplus-sharePatent US4649989 - Device for testing and/or repairing steam generator tubes
