HEAT-EXCHANGER AND METHOD FOR SEALING ITS TUBE PLATE AND HEAT-TRANSFER PIPE

摘要

PURPOSE: To provide a heat-exchanger which is structured to prevent the occurrence of gap corrosion between the pipe hole wall of a tube plate and the outer surface of a heat-transfer pipe. ;CONSTITUTION: A main part 10 of a heat-exchanger comprises a tube plate 12, a heat-transfer pipe 16 inserted in a tube hole 14 of the tube plate 12, a fixed part 18 fixing the heat-transfer pipe 16 to the tube plate 12, and a sealing part 20 for the tube plate 12 and the heat-transfer pipe 16. A fixed part for the heat-transfer pipe and the tube plate consist of a means similar to a conventional heat-exchanger. The seal part is positioned at the opening edge part on the drum side of the pipe hole. Formation of the seal part is such that after the heat-transfer pipe is securely inserted in the pipe hole, laser beams are positioned above the seal part in such a state to approach the interior of the heat-transfer pipe from the channel side of the tube plate and the constituting metal of the heat-transfer pipe is molten in the constitution metal of the tube plate and mutually fused through laser welding throughout the whole periphery of the inner periphery of the heat-transfer-pipe. This constitution seals together the tube plate and the heattransfer pipe at the opening edge part on the drum side of the pipe hole throughout the whole of the outer periphery of the heat-transfer pipe.;COPYRIGHT: (C)1996,JPO