Abstract: A device for producing finned heat transfer tubing of oval cross section by winding one or more continuous metal strips around the tubing in the form of spiral fins, the contact edge of the metal strip being shaped prior to winding to present a hook-shaped ledge with an acute enclosed angle, and the neutral axis for on-edge bending being shifted to the vicinity of the contact edge by applying to the strip a tensile stress and to its upper half additional transverse compression stress, using a stretch roller and a cooperating winding guide. A lathe-like machine semi-automatically winds two metal strips onto successive lengths of oval tubing, using a carriage with two pivotable winding arms and two strip reels.

Abstract: A device for the cold rolling of narrow flat lands on the cylindrical surface of heat exchanger tubing, just prior to the winding onto the tubing of one or more metal strips for the production of finned tubing, the device having pressure rollers on pressure levers carried by a journalled supporting spindle which rotates with the tubing, and a control sleeve inside the hollow spindle which, under the action of a linear actuator, interrupts the rolling action as desired, while the winding operation continues.

Abstract: A method and device for producing finned heat transfer tubing of oval cross section by winding one or more continuous metal strips around the tubing in the form of spiral fins, the contact edge of the metal strip being shaped prior to winding to present a hook-shaped ledge with an acute enclosed angle, and the neutral axis for on-edge bending being shifted to the vicinity of the contact edge by applying to the strip a tensile stress and to its upper half additional transverse compression stress, using a stretch roller and a cooperating winding guide. A lathe-like machine semi-automatically winds two metal strips onto successive lengths of oval tubing, using a carriage with two pivotable winding arms and two strip reels.

Abstract: A method for the cold rolling of narrow flat lands on the cylindrical surface of heat exchanger tubing, just prior to the winding onto the tubing of one or more metal strips for the production of finned tubing, the device having pressure rollers on pressure levers carried by a journalled supporting spindle which rotates with the tubing, and a control sleeve inside the hollow spindle which, under the action of a linear actuator, interrupts the rolling action as desired, while the winding operation continues.