Abstract: A coaxial finned tube heat exchanger is disclosed. The heat exchanger comprises a hollow shell (10), a tube (14) mounted coaxially within such shell and having radially extending outer fins (16) of substantially large radial dimension in relation to the tube diameter. A first heat exchange fluid is passed in the tube and means (12) are provided for passing a second heat exchanger fluid through the shell. A plurality of segmental cut baffles (18) are mounted between adjacent fins at a predetermined spacing within the shell so as to achieve a cross-flow pattern for the second fluid between the fins of the tube, and a pair of bypass flow blockers (22) are mounted longitudinally on the tip of the fins to block circumferential flow of the second fluid between the shell and the tips of the fins and so force the fluid flow between the fins.

Abstract: A heat transfer device having an augmented surface is disclosed. The device comprises a base wall of heat conductive material having a plurality of pyramid-fins formed integrally with the surface of the base wall. The pyramid-fins are regularly spaced apart in the range of about 80-500 pyramid-fins per square inch and have a height in the range of 0.015 to 0.040 inch. The base wall is preferably a cylindrical tube and the pyramid-fins are formed as a knurled diamond pattern around the outside periphery of the tube.

Abstract: A method of reforming the fins of a finned tube is disclosed. The method comprises forming a tube having a plurality of internal longitudinal fins with a V-notch at the tip of the fins, and reforming the fins of the tube over a shaped plug, in long lengths, to spread the tips of the V-notch so that the tips of the fins are wider than the fin thickness.