Method for manufacturing heat exchanger tubing

Abstract

In accordance with the teachings of the instant invention, methods and apparatus are set forth for the manufacture of discrete lengths of heat exchanger tubing comprised of a thin walled metallic tubular member having a plurality of spaced apart transverse grooves impressed into its outer surface, and expanded end portions whose inner cross sections form symmetrical polygons. Such tubing is manufactured in accordance with the instant invention by the steps of deforming a metal band in a longitudinal direction into a tubular member, continuously seam welding the longitudinal edges of the tubular member, continuously impressing spaced apart grooves into the outer surface of the welded tubular member, transversely cutting the tubular member along smooth portions of the tubular member between selected adjacent transverse grooves to form discrete tube lengths, and expanding the inner cross sections of the end portions of each of such lengths to form symmetrical polygons.

Dependencies are inferred from the claim text.