METHOD AND APPARATUS FOR FORMING A HEAT EXCHANGER TUBE WITH CLOSELY SPACED INTEGRAL FINS

摘要

Fins are formed on a copper heat exchanger tube by a plurality of rolling dies which roll grooves into the surface of the tube. The tube walls are supported by an internal mandrel. The pitch between the roll dies generally increases but at a decreasing rate from the lead roll die to the trailing roll die to accommodate axial elongation of the tube resulting from the radially pressures exerted on the tube by the roll dies and mandrel.