Tube bundle prodn. - eliminating internal seal weld and providing adequate access to each weld

摘要

The pipe bundle is assembled in supports and one end plate is welded in position in the conventional manner. The opposite end plate has pipe stumps welded to it in such a manner that the internal diameter of each pipe stump is identical and flush with the internal diameter of the hole in the end plate and the corresponding member of the tube bundle. The outside diameter of the stump corresponds with that of the tube. The lengths of the tubes are arranged such that their terminations are closest to the end plate in the centre and the distance between the tube end and end plate increases with increasing distance from the centre of the bundle. Intermediated pieces of the same internal and external diameter as the end plate stumps and the tubes are then welded into the gap between tube end and end plate stump to complete the assembly. The method is used for the assembly of heat exchanger bundles of length of the order of 10 to 40 m such as would be used for carrying sodium in nuclear power stations or for steam generators. Traditionally, the pipe bundle is assembled and the end plate is then moved into contact with the bundle ends and seal welds are run from the inside of the opening in the end plate between the plate and the tube end. The problem with this method is that the weld may be subjected to excessive bending moments and that inspection of the weld is extremely difficult. These problems are overcome by means of the above fabrication procedure.