| 摘要 |
A heat transfer tube (10), and a method of manufacturing a heat transfer tube (1 0), having an external surface that is configured for enhanced heat transfer perform ance in both refrigerant evaporating and condensing applications. The tube is suitable for us e in, for example, shell and tube type air conditioning condensers flooded evaporators, fa lling film evaporator, or a combination of flooded and falling film evaporator. The tube ha s at least one fin convolution (20) extending helically around its external surface (13). A pat tern of notches (30) extends at an oblique angle (.alpha.) across the fin convolutions at interv als about the circumference of the tube. There is a split spike (22) having two distal tips (2 3) between each pair of adjacent notches. The fin convolution, notches and split spikes are form ed in the tube by rolling the wall of the tube between a mandrel and, first, a gang of finning disks (63), second, a notching wheel (66) and third, a splitter wheel (67). Because of the i nteraction of the rotating and advancing tube and the notching wheel, during the manufacture o f the tube, the maximum width (Wt) of the spike is greater than the width (Wr) of the proxim al portion of the fin convolution.
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