Abstract: Disclosed is a tube bending system for forming a hairpin tube, the tube bending system including: a supply of lubricant; a supply of atomizing medium; a bend mandrel, the bend mandrel comprising: a mandrel body and a mandrel head, the mandrel head being positionable within a length of a tube to be bent, the mandrel head including a downstream end with an orifice configured for injecting lubricant into the tube.

Abstract: Disclosed is a tube bending system for forming a hairpin tube, the tube bending system including: a supply of lubricant; a supply of atomizing medium; a bend mandrel, the bend mandrel comprising: a mandrel body and a mandrel head, the mandrel head being positionable within a length of a tube to be bent, the mandrel head including a downstream end with an orifice configured for injecting lubricant into the tube.

Abstract: An apparatus for expanding and belling a tube is provided including a receiver for supporting a first end of the tube. A stripper block assembly orients a second end of the tube along an axis. The stripper block assembly includes a first grip and a second grip movable in and out of engagement with a surface of the tube. The apparatus also includes a movable belling tool axially aligned with the tube. The belling tool bells a desired length of the tube and supports the second end of the tube. An expander tool is arranged to pass through the axially aligned tube to expand the tube. The expander tool includes an expander rod and an expander bullet. A portion of the expander bullet has a diameter larger than the diameter of the tube.

Abstract: A heat exchanger includes a plurality of fins and a plurality of tubes passing a fluid therethrough, extending through the plurality of fins and radially expanded into an interference fit therewith. At least one tube of the plurality of tubes includes an outer diameter, an inner diameter, and a plurality of ridges extending from the inner diameter inwardly into an interior of the tube. A tube internal surface area per unit of length of the tube multiplied by the ratio of the outer diameter and tube wall thickness is equal to or greater than about 30.0.

Abstract: An apparatus for expanding and belling a tube is provided including a receiver for supporting a first end of the tube. A stripper block assembly orients a second end of the tube along an axis. The stripper block assembly includes a first grip and a second grip movable in and out of engagement with a surface of the tube. The apparatus also includes a movable belling tool axially aligned with the tube. The belling tool bells a desired length of the tube and supports the second end of the tube. An expander tool is arranged to pass through the axially aligned tube to expand the tube. The expander tool includes an expander rod and an expander bullet. A portion of the expander bullet has a diameter larger than the diameter of the tube.