Abstract: This invention provides an enhanced condensation heat-transfer tube, which is furnished with spiral fins on the outer surface. Axial spacing between the said fins regularly changes in width. In a preferred embodiment, the said fins regularly change in height along the axle. Such spiral fins with even changes in height and spacing change the surface tension of the condensate membrane between the fins outside of the tube, so as to enhance the “Gregorig” effect (average heat resistance reduces due to uneven thickness of condensate membranes). In this way, it further strengthens condensation heat transfer effects outside of the tube. At the same time, it accelerates flowing of the condensate to the bottom, enhances heat transfer effect, and improves the tube bundle effect.

Abstract: The present invention discloses strengthened heat transmission tubes for falling film evaporators. The tube includes a tube body of the heat transmission tube and fins disposed on an outside surface of a heat transmission section of the tube body. The fins spirally surround the outside surface of the tube body of the heat transmission tube along an axial direction. The roots of the fins are integrally connected with the tube body. Each of the fins has a cross sectional T shape. Interspaces between two neighboring fins along the axial direction of the tube form small holes for coolants flow and evaporation, and form circular shape channels along the spiral direction. Each T shape fin has fin troughs along peripheral direction. The outer surfaces of the fins are disposed with grooves or extrusion lugs that guide coolants flow. Internal tube body is disposed with internal teeth.