FABRICATION OF HEAT EXCHANGER TUBE BUNDLES

摘要

All-welded heat exchanger tube bundles, with integral mounting flanges, are fabricated by first flaring the ends of the tubes and then machining, by a rack hobbing process, three weld prep surfaces, arranged as half a hexagon, on the flared ends of the tubes. The machining is performed on one complete row of tubes at a time and, at the same time, the ends of solid stubs (which eventually become the mounting flanges) are similarly machined. A machining operation is performed on both an unwelded row of tubes, held in a fixture, and on a previously welded array of tubes in the tube bundle; after both of these operations, the two groups of weld prepped tubes may be welded together to add the new row of tubes to the bundle.